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 thoroughly to ensure optimal performance and longevity of your device.
Key Features
- True Open Ear Design: Experience ultimate comfort with a completely open-back design that allows sound to embrace the ears while maintaining situational awareness.
- 360° Excellent Sound Quality: Equipped with dual powerful 12mm dynamic driver units, modified PI composite beryllium diaphragms, and 30mW DAC sound card thrust for three-dimensional and concrete audio.
- Hearing Protection: The open-back design avoids common health concerns associated with traditional in-ear earplugs, preventing ear discomfort and potential hearing damage.
- Extended Battery Life: Enjoy up to 6 hours of listening time on a single charge, extended to up to 30 hours with the included charging case.
- IPX5 Water Resistance: Designed to resist water and sweat, making them suitable for workouts and outdoor activities.
- Bluetooth 5.4 Connectivity: Ensures stable and efficient wireless connection with your devices.
- HD Clear Calls: Provides clear voice transmission during phone conversations.
- Intuitive Touch Control: Easily manage playback, calls, and volume with simple touch gestures.
Product Overview

The Monster Open Ear AC210 Headphones with their compact charging case.

The open-ear design ensures comfort and awareness of surroundings, ideal for travel or daily use.

Detailed view of the 12mm dynamic drivers, engineered for high-definition sound quality.

Visual representation of the extended battery life, offering up to 30 hours of playback with the charging case.

The IPX5 water resistance rating ensures durability during intense workouts or light rain.
Setup
1. Charging the Headphones
Before first use, fully charge the headphones and the charging case. Place the headphones into the charging case. Connect the USB-C charging cable to the charging case and a power source. The indicator light on the case will show charging status.
- A full charge provides approximately 6 hours of listening time for the headphones.
- The charging case provides multiple additional charges, extending total playback time up to 30 hours.
2. Bluetooth Pairing
- Ensure the headphones are charged.
- Open the charging case. The headphones will automatically enter pairing mode, indicated by a flashing light on the earbuds.
- On your device (smartphone, tablet, computer), enable Bluetooth.
- Search for "Monster Open Ear AC210" in the list of available Bluetooth devices.
- Select "Monster Open Ear AC210" to connect. Once connected, a voice prompt will confirm the connection, and the indicator light will stop flashing.

Simple one-step Bluetooth pairing for quick connection to your devices.
Operating Instructions
1. Wearing the Headphones
The Monster Open Ear AC210 headphones are designed for a secure and comfortable fit. Gently place the earhook over your ear, ensuring the speaker part is positioned correctly near your ear canal without entering it. Adjust for optimal comfort and sound.

Proper wearing ensures both comfort and optimal audio experience.
2. Touch Controls
The headphones feature intuitive touch controls on each earbud. Refer to the table below for common functions:
| Action | Function |
|---|---|
| Click x 2 (Left/Right) | Answer/End Call, Play/Pause Music |
| Hold 2s (Left/Right) | Reject Call |
| Click x 3 (Left) | Previous Song |
| Click x 3 (Right) | Next Song |
| Click x 1 (Left) | Volume Down |
| Click x 1 (Right) | Volume Up |
Maintenance
- Cleaning: Use a soft, dry, lint-free cloth to clean the headphones and charging case. Do not use harsh chemicals or abrasive materials.
- 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.
- Battery Care: To preserve battery life, charge the headphones regularly, even if not used frequently. Avoid extreme temperatures.
- Water Resistance: While IPX5 rated, avoid submerging the headphones in water. Dry them thoroughly if they get wet from sweat or light rain.
Troubleshooting
| Problem | Solution |
|---|---|
| Headphones not pairing | Ensure headphones are charged. Turn off and on Bluetooth on your device. Forget the device in your Bluetooth settings and re-pair. |
| No sound from one earbud | Place both earbuds back into the charging case, close the lid, wait a few seconds, then open and try again. Check device audio balance settings. |
| Low volume | Increase volume on both the headphones via touch control and your connected device. |
| Poor call quality | Ensure microphone is not obstructed. Move closer to your connected device. Avoid noisy environments. |
| Headphones not charging | Check USB-C cable and power adapter. Ensure charging contacts on headphones and case are clean and dry. |
Specifications
| Feature | Detail |
|---|---|
| Model Name | Monster Open Ear AC210 |
| Connectivity Technology | Wireless (Bluetooth 5.4) |
| Ear Placement | Open Ear |
| Audio Driver Type | Dynamic Driver |
| Audio Driver Size | 12 Millimeters |
| Battery Life (Single Charge) | 6 Hours |
| Total Playback (with Case) | Up to 30 Hours |
| Control Type | Touch Control |
| Water Resistance Level | IPX5 Water Resistant |
| Frequency Range | 20 Hz - 20,000 Hz |
| Material | Plastic, Rubber, Foam/Silicone |
| Item Weight | 5.6 ounces |
What's in the Box
- Monster Open Ear AC210 Headphones (Left & Right)
- Charging Case
- USB-C Charging Cable
- Quick Guide (User Manual)
Warranty and Support
Monster products are designed and manufactured to the highest quality standards. For warranty information and customer support, please refer to the warranty card included in your product packaging or visit the official Monster website. If you have any questions or require assistance, please feel free to contact our professional support team.





