4-037 series :

The two-wire earphone kit provides excellent durability, reliability and performance in low-profile environment. This is ideal for demanding covert security applications where sound clarity and durability are of paramount importance. Apart from surveillance purposes.

The plastic earbud fits snugly to your ear canal.
Low-profile, flexible, transparent acoustic tube transmit sound in high quality; the transparent tube would be hardly noticed by others around you.

The hidden microspeaker is located in the side of PTT switch.

The throat mic is VOX ready. It can work in VOX mode with radios that come with built-in VOX function. For radios without built-in VOX, it can still work in PTT mode.

Specifications: 

Length of wires: 90 cm / 3 ft from plug to PTT VOX switch;

60 cm / 2 ft from PTT VOX switch to throat mic;

Transparent tube extendable to 30 cm / 1 ft from the microphone;

Weight: 40 g.

This earpiece can provide several plugs: