S21 TWS Bluetooth Earbuds User Manual

Product Overview

The S21 TWS Bluetooth earbuds are designed for a seamless wireless audio experience. The package includes the earbuds and a charging case.

Key Components:

• Earbuds: Left and Right earbuds, each featuring an MFB (Multi-Function Button) touch control, microphone, and indicator light.
• Charging Case: Houses and charges the earbuds, featuring a charging case indicator light and charging pins.
• Ear Caps: Replaceable ear tips available in three sizes (Small, Medium, Large) for a secure and comfortable fit.

Diagram Description: A visual representation shows the individual earbuds, highlighting the MFB touch button, microphone, indicator light, and charging contact pins. The charging case is also shown, with its indicator light and the space for earbuds. Ear caps are depicted separately.

Ear Cap Selection

We provide three sizes of ear caps (Large, Medium, Small). Please try different sizes to find the one that fits your ears best for optimal comfort and sound quality.

Diagram Description: An illustration shows the three sizes of ear caps labeled S, M, and L, with an indication to select the size that provides the best fit for the left and right ears.

Earphone Operation & Controls

Power On: Take out earbuds from the charging case, or touch and hold the MFB button on either earbud for 3 seconds until the blue light flashes once.

Power Off: Place earbuds back into the charging case, or touch and hold the MFB button for 5 seconds (when disconnected).

Button Controls:

• Play/Pause: Single tap the MFB button on either earbud.
• Answer/Hang Up Call: Single tap the MFB button on either earbud.
• Reject Incoming Call: Touch and hold the MFB button on either earbud for approximately 2 seconds.
• Next Track: Double tap the MFB button on the right earbud.
• Previous Track: Double tap the MFB button on the left earbud.
• Volume Up: Touch and hold the MFB button on the right earbud.
• Volume Down: Touch and hold the MFB button on the left earbud.
• Voice Assistant Activation: Triple tap the MFB button on either earbud.

Note: In standalone mode (using only one earbud), previous track and volume down functions may not be supported.

Pairing Instructions

1. Remove both earbuds from the charging case and peel off any insulating film from the charging contacts.
2. Place the earbuds into the charging case to charge them.
3. Take out both earbuds from the case. They will automatically turn on, pair with each other, and enter pairing mode (indicated by alternating red and blue lights on the master earbud). The slave earbud's indicator will turn off.
4. On your smartphone or device, enable Bluetooth and search for available devices.
5. Select "S21" from the list and connect. The master earbud's indicator will flash blue every 6 seconds once connected to the phone.

Troubleshooting Pairing: If earbuds cannot be found or do not enter pairing mode, turn off your phone's Bluetooth. With the earbuds flashing red/blue, quickly double-tap the MFB button on either earbud to re-initiate pairing. Then, delete the "S21" pairing record from your phone's Bluetooth list and search again.

Bluetooth Settings & Connectivity

Your device may be discoverable as "Qi iPhone" or similar. For pairing with Apple Watch, refer to the Watch app on your iPhone.

Diagram Description: A screenshot shows a phone's Bluetooth settings menu, displaying "S21" as a discoverable device.

Siri & Voice Assistant

Activate your device's voice assistant (like Siri or Google Assistant) by triple-tapping the MFB button on either earbud.

Charging

Charging Earbuds:

• Place the earbuds into the charging case. Charging begins automatically.
• The earbud indicator light shows red while charging and turns off when fully charged.
• If the battery is low, the red indicator light will flash.

Charging the Case:

• Connect a USB Type-C cable to the charging port on the case.
• The charging case indicator light shows red while charging and turns green when fully charged.
• If the charging case battery is low, the red indicator light will flash.
• The case supports automatic current limiting for chargers exceeding 5V 1A.

Note: For first-time use, fully charge both the earbuds and the charging case.

LED Indicator Status

Earbud Indicators:

• Power On: Blue light flashes for 1 second, then red/blue lights flash alternately.
• Power Off: Red light flashes for 1 second, then turns off.
• Search/Pairing: Red and blue lights flash alternately.
• Paired (Master Earbud): Red and blue lights flash alternately after successful pairing.
• Connected to Phone: Blue light flashes once circularly every 6 seconds.
• Low Battery: Red light flashes once every 6 seconds.
• Charging: Red light is solid.
• Fully Charged: Red light turns off.
• Music Play: No light.

Charging Case Indicators:

• Charging Case Charging: Red light is solid.
• Charging Case Full Battery: Green light is solid.
• Charging Earbuds: Red light is solid.
• Charging Case Low Battery: Red light flashes.

Parameter Specifications

Waterproof Rating

The earbuds feature an IPX8 waterproof nano-coating, providing effective protection against sweat and raindrops. They are suitable for activities like running and skiing but are not designed for swimming.

Signal Transmission Distance

Diagram Description: A visual indicates that the Bluetooth signal is stable and normal up to 10 meters (33 feet). Beyond 10 meters, the signal may become intermittent or drop.

Attentions and Warnings

Battery Warning:

This product contains a built-in lithium battery. To prevent explosion, do not expose the product to strong sunlight, fire, or dispose of it in fire.

General Attentions:

• Do not use corrosive liquids for cleaning. Clean with a soft, damp cloth if exposed to chemicals.
• Keep the charging case away from dripping or splashing water.
• Ensure the earbuds and USB-C charging port are dry before charging. Wipe with a dry cloth if wet.
• Do not use the product in extreme temperatures (below -10°C or above 60°C).
• Avoid throwing the product into fire.
• Prevent scratches by avoiding contact with sharp objects.
• Do not insert foreign objects into the earbuds, as this may damage internal components.
• Do not attempt to disassemble or repair the product yourself.
• For long periods of non-use (over one month), charge the product periodically to maintain battery health.
• Do not use power adapters with currents exceeding 2A, as excessive current can damage the battery.

FCC Caution

This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) this device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation.

Any changes or modifications not expressly approved by the party responsible for compliance could void the user's authority to operate the equipment.

This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation.

If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures:

• Reorient or relocate the receiving antenna.
• Increase the separation between the equipment and receiver.
• Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
• Consult the dealer or an experienced radio/TV technician for help.

The device has been evaluated to meet general RF exposure requirements and can be used in portable exposure conditions without restriction.