The Valken ZULU Spitfire airsoft tracer unit is a high-tech, feature-packed addition to the muzzle of any airsoft gun! Able to be used with airsoft rifles or airsoft pistols with an included 14 to 11mm thread adapter and built tough from rugged aluminum, the Valken Zulu Spitfire tracer unit is simple to charge with the its internal Lithium Polymer battery and included USB charging cable. Compatible with green tracer airsoft BB's and gel ammo, the Spitfire tracer unit features auto-on after 3 BB's are fired, an auto shutoff after 40 minutes idle to save battery power and simulates muzzle flash with included forward-facing LED's! An outstanding addition to any Valken ASL airsoft gun or airsoft pistol with a threaded barrel, the Valken ZULU Spitfire airsoft tracer unit adds a realistic effect and sleek, tactical look to your airsoft gun!