Monster AC312 Open-Ear Headphones, Bluetooth, 16.2 mm Drivers

Drivers: Monster AC312 Open Ear Headphones are wireless open-ear headphones with a microphone, USB-C charging, and a manufacturer-claimed 32-hour battery life. Their open design suits listeners who want to hear surrounding sounds while listening, though listing details differ on Bluetooth version and protection claims.

At a glance

Open-ear placement leaves the ears uncovered, supporting awareness of surrounding sounds while listening.
The listing describes a microphone with environmental-noise cancellation for calls.
Manufacturer copy claims up to 32 hours of playtime, but gives no operating-mode conditions.
A USB-C charging cable is named in the manufacturer’s contents list.

Price

$29.99Save 79%

Reference price: ~~$139.99~~

Price checked: Nov 14, 2026

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Pros and cons

Pros

Open-ear design suits listeners who prefer not to seal the ear canal and want ambient sound to remain audible.
Touch and button controls are both listed, offering more than one stated control method.
The USB-C charging interface is specified.

Technical specifications

21 specifications

Identity
Brand	Monster
Model	Ac312 Open Ear Headphones
Color	White

Audio
Driver type	Dynamic Driver
Driver size	16.2 millimeters
Impedance	32 ohm
Frequency response	20 hertz
Sensitivity	105

Connectivity and controls
Wireless connection listed	Bluetooth
Bluetooth version	5.3
Bluetooth range	33 feet
Control methods listed	Push Button, Touch
Charging interface	USB Type C
Headphone jack	3.5 mm Jack

Design and dimensions
Form factor	Open Ear
Weight listed	0.09 kg
Enclosure material	Plastic, Rubber, Silicone

Materials and protection
Water resistance listed	Moisture Resistant

In the listing
Advertised battery life	32H Playtime
Advertised water-resistance rating	IPX5 Waterproof
Advertised microphone feature	ENC Mic

What to know before buying

Listing details to confirm

The listing is inconsistent about Bluetooth version: the title and feature copy state 5.4, while the technical details state 5.3. Its IPX5 waterproof and 32-hour claims appear in promotional copy, while the technical water-resistance field says only “Moisture Resistant.” Confirm which specifications apply to the selected item. The 32-hour figure has no stated use mode or conditions.

What’s in the box

Included

Headphones
USB charging cable
User manual

Who is it for?

A good fit for

People seeking open-ear headphones for workouts, running, commuting, or music listening while staying aware of nearby sound.
Buyers who want wireless headphones with a microphone and USB-C charging.

Less suited to

Listeners who need a sealed fit or listed active noise cancellation for blocking outside sound.
Buyers who require a confirmed Bluetooth version, clearly specified water-resistance rating, or battery runtime under a particular listening mode.

Monster AC312 Open-Ear Headphones, Bluetooth, 16.2 mm Drivers · photo 2 — Additional product photo 2

Customer reviews on Amazon

5 / 5 · 1 ratings

5 stars100%100%
4 stars0%0%
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The supplied evidence contains only one aggregate rating and no written customer feedback. That single top-star rating is too limited to establish dependable customer consensus or identify specific strengths and concerns.

Frequently asked questions

Do these headphones block outside noise?

They use an open-ear design, and the listing names no noise control. Its ENC claim refers to the microphone for calls, not stated cancellation of sound for the listener.

Which Bluetooth version do they use?

The listing conflicts: title and feature text say Bluetooth 5.4, while the technical details say 5.3. Check the selected listing before buying.

Is the 32-hour battery claim guaranteed for every use?

The listing advertises 32 hours but gives no listening mode or test conditions, so it does not establish runtime for a particular use.

What is listed in the package?

The manufacturer’s contents list names the headphones, a USB charging cable, and a user manual.