E21 Smart Watch User Manual

What's in the Box

Your E21 Smart Watch package includes:

• Smart watch with bands × 1
• Charging cable × 1
• Quick start guide × 1

Charging Your Watch

Please fully charge your watch before its initial use.

1. Insert the USB plug of the charging cable into a USB charger.
2. Attach the other end of the cable to the charging contacts on the back of the watch. Ensure the pins on the charging cable lock securely with the port. A battery icon with the charging percentage will appear on the screen, indicating a secure connection.

Wearing Your Watch

All-day Wear and Exercise

For all-day wear when not exercising, wear the device on your wrist horizontally, about one finger's width below your wrist bone, lying flat, similar to how you would wear a traditional watch.

For optimized heart rate tracking:

1. Experiment with wearing the watch higher on your wrist during exercise. Moving the watch up a couple of inches can improve the heart rate signal due to increased blood flow. This position also helps prevent interference from wrist bending during activities like cycling or weightlifting.
2. Ensure the band is not worn too tightly. A tight band can restrict blood flow, potentially affecting the heart rate signal. During exercise, the watch should be snug but not constricting, slightly tighter than for all-day wear.

Pairing Your Watch

Install Letsfit App on Your Smartphone

Download the Letsfit App from the Apple Store or Google Play. You can also scan the QR codes provided to download the app.

Compatibility:

• iOS: 12.0 & above
• Android: 6.0 & above

Note: The Letsfit App is compatible with smartphones only, not tablets or PCs.

Account Registration and Login

Register an account using a valid email address. After registration, tap "Verified" to log in.

Pair the Watch with Your Phone

1. Turn on the Bluetooth on your smartphone.
2. Open the Letsfit App, navigate to the "Device" page, and tap "Pair device".
3. Tap the QR code icon [☐] and scan the QR code displayed on your watch to pair.
4. Alternatively, tap "E21" in the app to search for the device and initiate pairing.
5. Tap the checkmark icon [✔] on your watch to confirm the connection.

Notes on Pairing:

• Once connected, the watch will automatically search for and reconnect to your phone if the connection is lost or Bluetooth is restarted.
• Unbinding the watch from the app will reset its data and restart the device. Avoid unbinding unless a reset is necessary.
• The watch can only be paired with one smartphone at a time. Ensure the watch and smartphone are within 0.5 meters during pairing.

App Interfaces

The Letsfit App provides various interfaces for monitoring your health and device settings.

• Summary: Displays daily activity data, including workout minutes, active hours, steps, and calories burned. You can swipe down to sync data.
• Today's data: Allows you to view historical data by selecting a specific date.
• Device: After connecting the watch, you can customize watch faces, notification settings, do not disturb mode, brightness, alarms, sedentary alerts, and weather forecasts.

Getting to Know Your Watch

Function Button

• Press: Wake the screen, return to the home screen, go to the function list, or pause/resume the current activity.
• Hold: Power on or off the watch.

Touch Screen

• Swipe to navigate between different interfaces.
• Tap to enter a function.
• Swipe the screen to the right to return to the previous interface.
• Hold: Customize the home screen (watch face).

Notifications

The watch displays incoming messages and call alerts. For Android users, notifications are received only when the Letsfit App is running, connected to the watch, and "Notification Alerts" are enabled in the app.

Swipe Down

Access quick settings.

Swipe Right/Left

Navigate through different function interfaces such as Heart Rate, Blood Oxygen, Sleep, and Stress.

Heart Rate

Displays real-time and historical heart rate data.

Blood Oxygen

Measures and displays blood oxygen levels.

Sleep

Tracks sleep duration and stages.

Stress

Monitors stress levels and provides relaxation guidance.

Customize the Home Screen

After pairing, the home screen displays the time and date. To customize it:

1. Press and hold the watch home screen for two seconds.
2. Swipe left or right to select a desired watch face and tap to confirm.

Function Introduction

Press the watch function button to access the function list:

• Health: View daily activities, heart rate, blood oxygen, sleep data, and access breathing guides.
• Clock: Customize alarms, countdown timers, and use the stopwatch.
• Sport Record: Review the last 15 sports records.
• Music: Control music playback on your smartphone.
• Watch Faces: Customize the home screen appearance.
• Phone: Make and answer Bluetooth calls, view call history.
• Workouts: Track exercise data across various sports modes.
• Reminders: Set reminders via the Letsfit app, which will vibrate the watch.
• Weather: View weather forecasts for upcoming days, updated via your phone's network connection.
• Settings: Access basic watch settings and information.
• Flashlight: Activate the watch's torchlight.

1. Tracking Daily Activity Data

Tap "Health" and then "Activity" in the function list to view your daily steps, distance, and calories burned.

2. Monitoring Heart Rate

Tap "Health" and then "Heart Rate". The watch will measure your real-time heart rate. All-day heart rate data can be viewed on the watch or in the app. For accurate readings, wear the watch slightly higher and tighter on your wrist during exercise, and ensure your profile is complete in the app.

3. Measuring Blood Oxygen Level

Tap "Health" and then "Blood Oxygen" to start measurement. For accuracy, wear the watch two fingers below the wrist bone, snug but not too tight. Keep your arm still, chest-level, with the watch screen facing up during measurement.

4. Tracking Sports

The watch tracks exercise data in various workout modes.

Start a Sport

Tap "Workouts", then swipe to select your desired sports mode.

Set Goals

Before starting, you can set goals for time, distance, or calories burned.

GPS Connecting

(For outdoor sport modes) The watch searches for GPS signals upon starting an outdoor sport. Ensure the Letsfit app is running in the background, location services are enabled on your phone, and you are in an open area for a better signal. A countdown will appear once GPS is connected.

If the GPS signal is weak, outdoor running and walking can be started in non-GPS mode; your movement track will not be recorded.

During Sports

Swipe up or down to view exercise data. Swipe left to control music playback on your phone.

End the Sport

Press the function button and tap "End" to finish the exercise.

Notes on Sports Tracking:

• Detailed data and graphs are available in the app's "Summary" page after synchronizing.
• Movement tracks for outdoor cycling, running, or walking in GPS mode are viewable in the app's "Summary" page.
• Exercises shorter than 2 minutes are not saved.
• Ensure the watch has at least 10% battery before starting an exercise.

5. Bluetooth Phone Call

Make and answer calls directly from your watch, provided it is connected via Bluetooth for calls.

Answer Incoming Calls

Tap the green phone icon [☎] to answer, the red phone icon [⌛] to reject, or press the function button to ignore.

Make a Call

On your watch, select "Phone" from the function list. Use the "Dial Pad" to enter a number or "Contacts" to select a saved contact. Tap the green phone icon [☎] to initiate the call.

Set Favorite Contacts

In the Letsfit app, go to the "Device" page and tap "Favorite Contacts" to manage your contacts.

Notes on Phone Calls:

• Phone call notifications require "Notification alerts" to be enabled in the app.
• Calls will not be notified if "Do Not Disturb" (DND) is active on the app or watch.
• "Silent Mode On" disables the watch's ringtone.

6. Setting Alarms

Add, enable, or disable alarms on your watch by navigating to "Clock" → "Alarm".

7. Message Notification

The watch vibrates and displays message content for incoming notifications (e.g., Facebook, Twitter, Instagram). Ensure "Notification alerts" are enabled in the app and DND mode is off for notifications to be received.

8. Setting Reminder

Set reminders by navigating to "Reminders" on the "Device" page in the Letsfit app. You can specify the time and label for each reminder.

9. Controlling Phone Music

After connecting your watch to your phone, tap "Music" on the watch to control music playback on your phone. This function works with the music player currently running on your phone.

Basic Specifications

• Model No.: E21
• Sync: Bluetooth 5.3
• Screen: 1.69" TFT LCD
• Waterproof Rating: IP68
• Working Time: 6-8 days
• Input: DC 5V/1A
• Battery Capacity: 250 mAH
• Working Voltage: 5V-500mAh
• Working Temperature: -10°C to 40°C

Troubleshooting

Failure to Re-pair the Watch

1. On the watch, swipe up the home screen, tap the settings icon [⚙], and select "Reset". This will reset the watch data and restart it.
2. Select the watch language and enter the QR code interface.
3. Use the Letsfit app to scan the QR code on your watch to pair.
4. If pairing still fails, ensure your smartphone's Bluetooth is enabled and the watch is not connected to other devices.
5. Search for the device in the app ("Device" → "Pair device" → "E21").
6. Keep the smartphone and watch within 0.5 meters and the watch screen active during pairing.

Occasional Failure to Connect with Bluetooth

Reboot your smartphone or restart its Bluetooth connection.

Failure to Receive Message/Call Notifications

Ensure the watch is connected to your smartphone via the app. Check the following:

1. In your smartphone's Settings, find the Letsfit app and enable Location and all Notifications.
2. Ensure your phone's Bluetooth is on and the watch is paired within the Letsfit app.
3. In the Letsfit app, go to "Device" → "Notification Alerts" and enable the feature.
4. Verify that the "Do Not Disturb" function is not enabled on the watch or in the app.

The Watch is Disconnected from the Letsfit App

Disconnection may occur if:

• Smartphone Bluetooth is off or exceeds the connection range (approx. 10 meters, reduced by obstacles).
• The Letsfit app is closed on the phone.

To reconnect:

1. Restart your phone's Bluetooth.
2. Close all background processes on your smartphone, restart the Letsfit app, and the watch should reconnect automatically.

Blood Oxygen Level Measurement Accuracy

Blood oxygen measurements can be affected by factors like movement, watch placement, skin temperature, and perfusion. For accurate readings:

• Wear the watch a finger-width below the wrist bone, snug but comfortable.
• Remain still during measurement, with your wrist flat and the watch facing up. Resting your arm on a table can help.

Disclaimer: The E21 Smart Watch blood oxygen sensor is not a medical device. Consult a doctor for any medical concerns.

Warranty

Letsfit offers a one-year warranty on all devices, covering manufacturing defects. For any questions or issues, please contact customer support.

Important Safety Instructions

The E21 Smart Watch contains electronic components. Improper use can lead to injury. To minimize risks:

• Avoid exposing the device to liquids, moisture, or rain while charging. Do not charge a wet device.
• Keep the device clean and dry. Avoid abrasive cleaners.
• Consult a physician before use if you have pre-existing conditions that may be affected by the device.
• Do not wear the device too tightly. Discontinue use and consult a doctor if you experience heat, irritation, or discomfort.
• Avoid extreme temperatures and open flames.
• This product is not a toy. Keep out of reach of children and pets.
• Do not attempt to disassemble, repair, or modify the device, as this voids the warranty and may cause hazards.
• Contact support if any parts require replacement.
• Do not use the device in saunas or steam rooms.
• Dispose of the device and battery according to local regulations.
• Do not use the device display for notifications or navigation while driving or in situations where it could cause distraction or hazard. Always be aware of your surroundings during exercise.

Battery Warnings

The device uses a lithium-ion battery. Follow these guidelines to prevent hazards:

• Do not disassemble, modify, puncture, or damage the battery.
• Do not attempt to remove the non-user-replaceable battery.
• Avoid exposing the battery to fire, explosion, or other hazards.

Health Warnings

• Consult your physician before use if you have a pacemaker or other internal electronic devices.
• The optical heart rate monitor uses green light; consult a physician if you have epilepsy or are sensitive to flashing lights.
• Always consult your physician before starting or modifying an exercise program.
• The device and its data are intended for general fitness and wellness, not medical diagnosis or treatment.
• Heart rate and blood oxygen readings are for reference only.
• Heart rate monitor accuracy can vary based on physical characteristics, device fit, and activity type/intensity.
• The watch relies on sensors; data provided is an estimation and may not be completely accurate.
• Individuals with eczema, allergies, or asthma may be more prone to skin irritation. Remove the device if discomfort or irritation occurs. Consult a doctor if symptoms persist.
• Clean and dry the watch and band regularly, especially after sweating, to prevent skin irritation.
• Give your wrist a break by removing the band for an hour after extended wear to prevent irritation from prolonged rubbing and pressure.

Maintenance

• Regularly clean your wrist and the smart watch, particularly after sweating or exposure to substances like soap or detergent.
• Use a soapless detergent, rinse thoroughly, and wipe with a soft towel. Avoid household cleansers.
• While water-resistant, wearing a wet band can irritate the skin. Clean and dry bands thoroughly after they get wet before wearing them again.
• Ensure your skin is dry before putting the bands back on.
• Avoid contact with sharp objects to prevent scratches.
• For light-colored bands, minimize contact with dark clothing to prevent color transfer.