The BT3 is modular: the earpiece connectors are interchangeable, so the adapter can be fitted to many detachable-cable in-ear monitors. The package contains three connector pairs: MMCX, standard 2-pin (0.78 mm) and MEE audio DC.

When switching in-ear monitors, only the connector pair needs to be changed, not the adapter. The connector type must match the socket of the in-ear monitor; the four available types and their compatibility are shown in the row below.

The BT3 supports the LDAC, aptX Lossless, aptX Adaptive, aptX HD and LC3 codecs. The codec actually used depends on the connected source device and its settings, so the BT3 offers modern wireless audio with a variety of devices.

LDAC enables high-resolution transmission with audio formats up to 32-bit/96 kHz. According to the manufacturer, aptX HD and aptX Lossless offer CD-quality wireless streaming, while aptX Adaptive offers low-latency, robust, high-resolution audio. The full supported list: SBC, LC3, aptX, aptX Adaptive, aptX HD, aptX Lossless and LDAC.

The BT3 is based on Bluetooth 5.4 and supports next-generation Auracast technology alongside traditional Bluetooth. With multipoint it can connect to two devices at once, such as a phone and a tablet, so re-pairing between them is not necessary.

Bluetooth multipoint maintains a simultaneous connection to two devices, while Auracast builds on the efficient LC3 codec to enable group and multi-device audio on an LE audio foundation. The operating range is 10 m, and the adapter supports the A2DP, HSP, HFP and AVRCP profiles.

With the dedicated EQ button the sound can be adjusted on the fly to suit the genre or the environment. A single press switches between four audio modes, from balanced to bass boost.

Dynamic Audio Enhancement (DAE) is controlled with the EQ button of the adapter, so the selected sound character applies to the connected in-ear monitor. The Balanced mode offers sound without additional tonal emphasis, Bass Boost emphasises bass response and depth, Vocal Boost the midrange, and Dynamic both the low and the high range.

The built-in microphone of the BT3 can be used for video conferences and phone calls with compatible devices, so the same in-ear monitors are suitable for both music and conversation. With the dedicated mute button the microphone can be switched off and on in a single press during a call or conference.

The microphone is omnidirectional with a frequency response from 100 Hz to 10 kHz and a sensitivity of -42 dB ± 3 dB, a suitable range for speech. The HSP and HFP profiles enable the headset and hands-free functions.

The controls of the adapter are located on the cable, so they are simple to access even while listening. This is where the EQ button that switches audio modes and the microphone mute button are found.

There is 34 cm of cable between the control modules and 50 cm between the two earpiece connectors, which gives a comfortable layout when worn around the neck. The adapter weighs only 17 g net.

The built-in flexible earhooks and the sliding cable cinch keep the in-ear monitors comfortably and securely in place. They do not need readjusting during long use and movement.

Over-ear wear distributes the cable weight behind the ear and around the neck, and the sliding cable cinch allows the length of the neckband to be adjusted. A stable fit helps the in-ear monitors to seal consistently, and therefore to deliver consistent bass.