Introduction
Welcome to the instruction manual for your new Monster Open Ear AC311 OWS Bluetooth 5.4 Headphones. These open-ear wireless headsets are designed for comfort and performance, featuring IPX5 waterproofing, AI noise cancelling for calls, and a secure ear hook design, making them ideal for sports and daily use. This manual provides essential information on setup, operation, maintenance, and troubleshooting to ensure you get the best experience from your device.

Monster Open Ear AC311 Headphones with Charging Case
Package Contents
Please check the package for the following items:
- Earphone (L & R) x 2
- Charging Case x 1
- Package Box x 1
- Type-C Charging Cable x 1
- User Manual x 1
- Warranty Card x 1
- Certificate Of Conformity x 1

Visual representation of the Monster AC311 package contents
Specifications
| Brand | Monster |
| Model | Open Ear AC311 |
| Bluetooth Version | 5.4 |
| Speaker Specification | Φ16.2mm |
| Audio Decoding | SBC |
| Playback Time (50% volume) | About 7 hours |
| Talking Time (50% volume) | About 5 hours |
| Headset Battery Capacity | 50mAh |
| Charging Case Battery Capacity | 300mAh |
| Headset Charging Time | About 1.5 hours |
| Charging Case Charging Time | About 2 hours |
| Charging Case Recharges Headsets | About 2.5 times |
| Charging Port | Type-C (5V/0.5A) |
| Waterproof Level | Headset IPX5, Charging case not waterproof |
| Material | ABS, Plastic |
| Maximum Wireless Range | 10m-20m |
| Sound Isolating | Yes |
| Earcups Type | Sealed |
| Driver Diameter | 16.2mm |
| Impedance Range | Up to 32 Ω |
| Frequency Response Range | 20 - 20000Hz |
| Sensitivity | 92dB |
| Resistance | 32Ω |
| Vocalism Principle | Dynamic |
| Communication | True wireless |
| Connectors | Type-C |
| Style | Ear Hook |
| Features | Waterproof, With microphone, Volume Control, Control Button, AI Noise Cancelling |

Detailed technical parameters for the Monster AC311 headphones
Setup Guide
1. Charging the Headphones and Case
Before first use, ensure both the headphones and the charging case are fully charged.
- Place the headphones into the charging case.
- Connect the Type-C charging cable to the charging port on the case and to a 5V/0.5A power source.
- The headphones take approximately 1.5 hours to fully charge. The charging case takes approximately 2 hours to fully charge.
- A fully charged case can recharge the headphones about 2.5 times.

Illustration of battery life and charging duration for the AC311
2. Bluetooth Pairing
The Monster AC311 headphones feature automatic pairing for convenience.
- Open the charging case. The headphones will automatically enter pairing mode.
- On your device (smartphone, tablet, etc.), enable Bluetooth.
- Search for "Monster AC311" in the list of available Bluetooth devices and select it to connect.
- Once connected, the headphones will automatically pair with your device whenever you open the charging case and Bluetooth is enabled on your device.

Diagram illustrating the advanced Bluetooth 5.4 chip for secure and stable connection
Operating Instructions
The Monster AC311 headphones utilize touch controls for various functions. Refer to the diagram below for specific gestures.
Touch Controls:
- Answer/Hang up Call: Single tap (x1) on either L or R earbud.
- Reject Call: Long press (2s) on either L or R earbud.
- Activate Voice Assistant: Long press (2s) on either L or R earbud.
- Play/Pause Music: Single tap (x1) on either L or R earbud.
- Previous Song: Triple tap (x3) on the Left (L) earbud.
- Next Song: Triple tap (x3) on the Right (R) earbud.
- Volume Down: Double tap (x2) on the Right (R) earbud.
- Volume Up: Double tap (x2) on the Left (L) earbud.

Visual guide to the touch controls for calls and music playback
AI Noise Cancelling for Calls:
The headphones are equipped with Smart AI call noise reduction technology, which effectively filters environmental noise interference, ensuring clearer conversations similar to face-to-face communication.

Illustration of AI noise cancelling technology enhancing call clarity
Restore Factory Settings:
To restore the headphones to their factory default settings, perform 6 consecutive taps on the touch key of both the left and right earbuds while they are powered on. The headphones will automatically power off and reset.
Maintenance
Proper care will extend the life of your Monster AC311 headphones.
- Cleaning: Gently wipe the earbuds with a soft, dry, lint-free cloth. Do not use harsh chemicals or abrasive materials.
- Water Resistance: The headphones are IPX5 waterproof, meaning they are resistant to sweat and light splashes of water. They are suitable for exercise and outdoor activities. Note: The charging case is NOT waterproof. Avoid exposing the charging case to water or moisture.
- Storage: When not in use, store the headphones in their charging case to protect them from dust and damage. Store in a cool, dry place away from extreme temperatures.
- Battery Care: To maintain battery health, avoid fully discharging the headphones and charging case frequently. Charge them regularly, even if not used for extended periods.

Demonstration of the headphones' IPX5 waterproof capabilities
Troubleshooting
If you encounter issues with your Monster AC311 headphones, try the following solutions:
- No Sound/Connectivity Issues:
- Ensure the headphones are charged.
- Make sure Bluetooth is enabled on your device.
- Try unpairing and re-pairing the headphones with your device.
- Ensure the headphones are within the 10-20m wireless range of your device.
- Restart your device and the headphones.
- One Earbud Not Working:
- Place both earbuds back into the charging case, close the lid, and then open it again to reset the connection.
- Try restoring factory settings (see Operating Instructions).
- Charging Problems:
- Check the charging cable and adapter for damage.
- Ensure the charging port on the case is clean and free of debris.
- Try a different Type-C cable and power source.
- Touch Controls Unresponsive:
- Ensure your fingers are clean and dry when using touch controls.
- Try restarting the headphones by placing them in the case and taking them out.
User Tips
Here are some tips to enhance your experience with the Monster AC311 headphones:
- Comfortable Fit: The ergonomic ear hook design is meant for stability. Adjust the ear hook gently to find the most comfortable and secure fit for your ear.
- Open-Ear Awareness: As open-ear headphones, they allow you to stay aware of your surroundings while enjoying audio. This is particularly useful for outdoor activities like running or cycling.
- Voice Assistant: Utilize the voice assistant feature for hands-free control of your device, making calls, sending messages, or getting directions without touching your phone.
- Regular Cleaning: Regularly clean the earbuds, especially the sound outlets, to prevent wax buildup and maintain optimal sound quality.

The ergonomic design ensures a stable and comfortable fit
Warranty and Support
Your Monster Open Ear AC311 headphones come with a standard manufacturer's warranty. Please refer to the included Warranty Card for detailed terms and conditions. For technical support, service, or warranty claims, please contact the authorized Monster distributor or the point of purchase.
Product Video
Official product video demonstrating unboxing, features, and controls of the Monster Open Ear AC311 headphones.





