The G&G UVT106 2.0 Tracer Unit is the smallest tracer unit we've ever seen. Built-in rechargeable 3.7v Li-Po battery. Illuminates a UV light when it senses it firing. 14mm CCW fits on most airsoft guns with threads.
Made of Aluminum outer. Dimensions: It's 51.5mm long and 27mm wide allowing it to fit inside most rail systems. Built-in battery charges on standard micro USB adapters.