4-008 series (with Mini Din Plug):

Black Surveillance Kits w/Extended Wear Comfort Earpieces include a Low Noise enhancement  already attached for extra comfort and convenience.

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, it is also commonly used for security at airports, casinos, manufacturing plants, croed-control at conventions and concerts, and other working environment requiring discret communications.

This earpiece can provide several plugs: