Introduction
Thank you for choosing the Monster Open Ear AC328 Wireless Earbuds. These open-ear headphones are designed to provide a comfortable listening experience while maintaining awareness of your surroundings. Featuring advanced Bluetooth 6.0 technology, clear call noise reduction, and long battery life, the AC328 earbuds are ideal for sports, travel, and daily use. Please read this manual carefully to ensure proper use and optimal performance of your device.

Image: The Monster Open Ear AC328 Wireless Earbuds and their compact charging case. The earbuds feature an open-ear design for comfort and situational awareness.
Package Contents
Please verify that all items listed below are included in your package:
- 1 x Monster Open Ear Headphones (AC328)
- 1 x Charging Case
- 1 x USB-C Cable
- 1 x Quick Start Guide
- 1 x Warning Card
Product Overview
The Monster Open Ear AC328 earbuds are engineered for comfort, sound quality, and practical use. Key features include:
- Open Ear Design: Allows natural sound entry, reducing pressure on the eardrum and promoting ear health. This design ensures comfort for extended listening sessions and maintains environmental awareness.
- Call Noise Reduction (ENC): Advanced Environmental Noise Cancellation technology provides clear conversations by effectively reducing background noise.
- Pure Monster Sound: Equipped with a 14.2mm diameter speaker, delivering a powerful and dynamic sound range.
- Ultra-Long Battery Life: Up to 8 hours of continuous playback on a single charge, extended to 32 hours with the charging case.
- Upgraded Bluetooth 6.0 Technology: Ensures a low-latency, stable connection with a range of up to 10 meters (33 feet).
- Lightweight and Portable: Ergonomic design for comfortable fit and easy portability.
- Water Resistant Design: Suitable for sports and outdoor activities.

Image: A visual comparison highlighting the comfort and safety benefits of the open-ear design compared to traditional in-ear headphones, which can cause discomfort or potential hearing issues.

Image: Illustrates practical benefits of open-ear earbuds, such as staying aware of surroundings outdoors, safe travel by car, clear calls, and enjoying music while remaining connected to the environment.
Setup
Charging the Earbuds and Case
Before first use, fully charge the earbuds and the charging case. Connect the provided USB-C cable to the charging port on the case and a power source. The indicator light on the case will show charging status.

Image: Depicts the battery life of the earbuds, showing over 8 hours of single charge playtime and over 32 hours of total playtime with the charging case.
Wearing the Earbuds
Follow these steps for a comfortable and secure fit:
- Confirm to take the earbuds as shown in the figure.
- From top to bottom, place the ear hook behind your ear.
- Adjust by twisting for comfort and secure fit.
- Complete.

Image: A four-step diagram illustrating the correct method to wear the open-ear earbuds, ensuring a secure and comfortable fit behind the ear.
Pairing with a Bluetooth Device
1. Open the charging case. The earbuds will automatically enter pairing mode.
2. On your device (smartphone, tablet, etc.), enable Bluetooth.
3. Search for "Monster Open Ear AC328" in the list of available devices.
4. Select it to connect. Once connected, you will hear a confirmation tone, and the indicator light on the earbuds will change.

Image: Demonstrates the fast and stable Bluetooth 6.0 connection process, showing a phone screen successfully paired with the Monster Open Ear AC328 earbuds.
Operating Instructions
The Monster Open Ear AC328 earbuds feature intuitive touch controls. Refer to the diagram below for specific functions:

Image: A detailed diagram illustrating the touch control functions of the earbuds, including single clicks, double clicks, triple clicks, and long presses for various operations like volume, playback, calls, and voice assistant.
| Action | Left Earbud (L) | Right Earbud (R) |
|---|---|---|
| Single Click | Volume - | Volume + |
| Double Click (x2) | Pause/Play | Pause/Play |
| Double Click (x2) during call | Answer Calls / Hang Up | Answer Calls / Hang Up |
| Triple Click (x3) | Previous Song | Next Song |
| Long Press (3s) | Spatial Audio | Voice Assistant |
Maintenance
To ensure the longevity and optimal performance of your Monster Open Ear AC328 earbuds, follow these maintenance guidelines:
- Cleaning: Regularly wipe the earbuds and charging case with a soft, dry, lint-free cloth. Do not use abrasive cleaners, alcohol, or chemical solvents.
- Water Resistance: The earbuds are water-resistant, suitable for sweat and light rain. Do not submerge them in water or expose them to strong water jets. Ensure they are dry before placing them back in the charging case.
- Storage: When not in use, store the earbuds in their charging case to protect them from dust and damage. Store in a cool, dry place away from extreme temperatures.
- Charging: Use only the provided USB-C cable or a certified equivalent for charging. Avoid overcharging.

Image: Shows the earbuds with water droplets, visually representing their water-resistant capabilities, making them suitable for active use.
Troubleshooting
If you encounter issues with your Monster Open Ear AC328 earbuds, try the following solutions:
| Problem | Possible Solution |
|---|---|
| Earbuds not pairing | Ensure earbuds are charged. Place them back in the case, close, then reopen to re-enter pairing mode. Turn off and on Bluetooth on your device. Forget the device from your Bluetooth list and try pairing again. |
| No sound from one earbud | Check battery level of both earbuds. Try resetting the earbuds (refer to Quick Start Guide for specific reset instructions if available). Re-pair with your device. |
| Low volume or poor sound quality | Adjust volume on both earbuds and your connected device. Ensure earbuds are clean and free of debris. Check for obstructions in the speaker area. |
| Earbuds not charging | Ensure the charging cable is securely connected to both the case and power source. Try a different USB-C cable or power adapter. Clean the charging contacts on the earbuds and inside the case. |
| Bluetooth connection unstable | Ensure your device is within the 10-meter (33-foot) Bluetooth range. Avoid obstacles between the earbuds and your device. Minimize interference from other wireless devices. |
Specifications
| Feature | Detail |
|---|---|
| Model Name | Monster Open Ear AC328 |
| Wireless Communication Technology | Bluetooth 6.0 |
| Form Factor | Open Ear, In Ear |
| Color | Black |
| Item Weight | 5 Grams (each earbud) / 0.176 ounces (total product) |
| Battery Life (Earbuds) | Up to 8 hours (single charge) |
| Total Playtime (with Case) | Up to 32 hours |
| Charging Port | USB-C |
| Speaker Diameter | 14.2mm |
| Water Resistance | Yes (suitable for sports) |
| Manufacturer | Monster |
Warranty and Support
For warranty information and technical support, please refer to the warranty card included in your package or visit the official Monster website. Keep your purchase receipt as proof of purchase for warranty claims.
For further assistance, you may contact Monster customer service through their official channels.





