Check out this review by the Fludblud on Acetech's AT-1000 Trace Unit... "Here is my personal review of the Acetech AT-1000 Tracer Unit. Attached using a 14mm CCW thread and powered by 4x AAA batteries enough to last 100,000 rounds at 1800rpm, the AT-1000 provides a bright and long lasting solution for all your airsoft tracer needs."