Introduction
Thank you for choosing the Monster Open Ear AC210 Headphones. This manual provides essential information for setting up, operating, and maintaining your new headphones. Please read it carefully to ensure optimal performance and longevity of your device.
The Monster Open Ear AC210 headphones are designed for comfort and situational awareness, allowing you to enjoy audio while remaining connected to your surroundings. They feature an open-ear design, flexible ear hooks, and advanced audio technology for a clear and immersive listening experience.
What's in the Box
Carefully unpack your Monster Open Ear AC210 headphones and ensure all items are present:
- Monster Open Ear AC210 Headphones (Left & Right)
- Charging Case
- USB-C Charging Cable
- Quick Guide
- User Manual (this document)

Image: All components included in the Monster Open Ear AC210 package.
Product Overview
The Monster Open Ear AC210 headphones feature an innovative design for comfort and performance.
Key Features:
- Open Ear Design: Allows ambient sound awareness for safety and comfort.
- Flexible Earhook: Ensures a secure and comfortable fit without entering the ear canal.
- Lightweight Construction: Designed for extended wear without discomfort.
- Hearing Protection: Reduces common health concerns associated with traditional in-ear headphones.
- Advanced Audio: Dual powerful 12mm dynamic driver units and modified PI composite beryllium diaphragms deliver three-dimensional sound.
- IPX5 Water Resistance: Resistant to sweat and light splashes, suitable for fitness and outdoor activities.

Image: A user wearing the Monster Open Ear AC210 headphones, illustrating the open-ear design and comfort features.

Image: Detailed view of the 12mm dynamic driver components for high-definition sound.
Setup
1. Charging the Headphones and Case
Before first use, fully charge the headphones and the charging case. The charging case provides additional battery life for your headphones.
- Place the headphones into the charging case.
- Connect the USB-C charging cable to the charging port on the case and to a power source (e.g., USB wall adapter, computer USB port).
- The indicator lights on the case will show the charging status. Refer to the Quick Guide for specific light patterns.
- A full charge provides up to 6 hours of listening time for the headphones, and the charging case extends this to a total of 30 hours.

Image: The Monster AC210 headphones and charging case, highlighting battery life.

Image: The charging case with battery life indicators.
2. Pairing with a Bluetooth Device
The Monster Open Ear AC210 headphones use Bluetooth 5.4 for a stable and efficient wireless connection.
- Open the charging case. The headphones will automatically enter pairing mode.
- On your device (smartphone, tablet, laptop), go to the Bluetooth settings.
- Search for available devices and select "Monster Open Ear AC210" from the list.
- Once connected, your device will indicate successful pairing.
The headphones are compatible with iOS and Android devices, as well as other Bluetooth-enabled devices like laptops and smart speakers.

Image: Bluetooth one-step pairing process shown on a smartphone.

Image: Simple one-click pairing for the Monster Open Ear AC210.
Operating Instructions
Wearing the Headphones
For optimal comfort and sound, ensure the headphones are worn correctly:
- Pick up the headphones.
- Place the main body of the earbud above your ears.
- Rotate the earhook upward along the auricle until it sits comfortably and securely in the appropriate position.
- Ensure the sound outlet is positioned correctly near your ear canal without entering it.

Image: Step-by-step guide on how to wear the headphones.

Image: A user demonstrating the safe and comfortable fit of the headphones.
Smart Touch Controls
The headphones feature intuitive touch controls on both the left (L) and right (R) earbuds:
| Action | Function |
|---|---|
| Click x 2 (L or R) | Answer / End Call |
| Hold x 2s (L or R) | Reject Call |
| Click x 2 (L or R) | Play / Pause Music |
| Click x 3 (L) | Previous Song |
| Click x 3 (R) | Next Song |
| Click x 1 (L) | Volume Down |
| Click x 1 (R) | Volume Up |

Image: Visual guide to touch control functions.
Maintenance
Proper maintenance ensures the longevity and performance of your Monster Open Ear AC210 headphones:
- Cleaning: Use a soft, dry, lint-free cloth to clean the headphones and charging case. Do not use harsh chemicals, cleaning solvents, or strong detergents.
- 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.
- Water Exposure: While IPX5 water-resistant, avoid submerging the headphones in water. Dry them thoroughly if they get wet from sweat or light rain before placing them back in the charging case.
- Charging: Only use the provided USB-C cable or a certified equivalent for charging.

Image: The headphones are suitable for workouts due to their water-resistant design.

Image: The headphones are resistant to water and sweat.
Troubleshooting
If you encounter issues with your Monster Open Ear AC210 headphones, try the following solutions:
No Sound or Poor Sound Quality:
- Ensure the headphones are properly paired and connected to your device.
- Check the volume levels on both your headphones and your connected device.
- Make sure the headphones are charged.
- Move closer to your device to avoid interference or range issues.
- If sound is too loud or distorted, try adjusting the volume on your device.
Headphones Not Pairing or Disconnecting Frequently:
- Ensure Bluetooth is enabled on your device.
- Turn off and then turn on Bluetooth on your device.
- Forget the "Monster Open Ear AC210" from your device's Bluetooth list and attempt to pair again.
- Ensure the headphones are fully charged.
- Restart your connected device.
Headphones Not Charging or Holding Charge:
- Ensure the charging cable is securely connected to both the case and the power source.
- Verify that the power source is active.
- Clean the charging contacts on both the headphones and the case with a dry cotton swab.
- Try a different USB-C cable or power adapter.
Headphones Falling Off or Uncomfortable Fit:
- Review the "Wearing the Headphones" section to ensure correct placement and rotation of the earhooks.
- Adjust the flexible earhooks gently to find a secure and comfortable position for your ear shape.
Specifications
| Feature | Detail |
|---|---|
| Model Name | E29 |
| Connectivity Technology | Wireless (Bluetooth) |
| Bluetooth Version | 5.4 |
| Ear Placement | Open Ear |
| Earpiece Shape | Open-ear |
| Audio Driver Type | Dynamic Driver (12mm) |
| Battery Life (Headphones) | Up to 6 Hours |
| Total Battery Life (with Case) | Up to 30 Hours |
| Charging Interface | USB-C |
| Water Resistance Level | IPX5 Water Resistant |
| Control Method | Touch |
| Compatible Devices | Cellphones, Tablets, Laptops, Desktops, Smart Speaker |
| Item Weight | 5.3 ounces |
| Manufacturer | Monster |
| Color | Black |
| Impedance | 110 Ohms |
Safety Information
Please observe the following safety guidelines when using your Monster Open Ear AC210 headphones:
- Do not use the headphones at excessively high volumes for prolonged periods to prevent hearing damage.
- Maintain awareness of your surroundings, especially when using the headphones in traffic, while cycling, or during other activities that require attention to ambient sounds.
- Keep the headphones and charging case away from extreme temperatures, direct sunlight, and open flames.
- Do not attempt to disassemble, repair, or modify the headphones or charging case. This may void the warranty and pose a safety risk.
- Keep out of reach of children and pets.

Image: The open-ear design allows users to stay safe by hearing their surroundings.
Warranty and Support
For any questions or assistance with your Monster Open Ear AC210 headphones, please contact our professional support team. We are committed to resolving any issues you may encounter.
Please refer to the Quick Guide or product packaging for specific warranty details and contact information.





