Allows you to listen to audio wirelessly for greater freedom of movement. Up to four WM 08 Modules can be connected to an EQUINOX detector for group training. Has a 3.5mm (1/8-inch) headphone jack, and also has a threaded socket to use with EQUINOX waterproof headphones. Note that the WM 08 itself is not waterproof. USB charging cable with magnetic connector included.