Another install guide from Evike.com as Matt tells more about the M32H Headset from Earmor and how to install it on a FAST Helmet... "The Earmor M32 comes with helmet rail adapter set for FAST MT Helmets, ideal for advanced tactical uses. It comes with MIL-STD 4 pin plug for PTTs (Nexus TP-120; Not compatible with Ztac PTTs), and detachable boom mic designed makes both lefty and righty using it comfortably, helps user having unhindered communication even in deafening combat situations."