ASG B&T Compact Tracer Unit Head Gear Electronics: Compatible with all Wolverine Electronics: Compatible with all Wolverine Airsoft Electronics + Electro Mechanical wire harness With a superior finish this awesome looking barrel extension tube features a screw on lock with a ratchet mechanism for a quick and tight fit on to the flash hider and outer barrel of your replica which can be adjusted with a turn of a screw to be a more secure and permanent fit This extremely small and short tracer unit uses a compact powerful flash to charge your tracer BB's with light making them self illuminating and puts fear in your opponents