This Madbull tracer unit is a GEMTECH style silencer which simply screws on to CCW 14mm threading on the end of the outer barrel. When turned activated (via the external switch), firing a BB through the silencer will automatically trigger a very short, very bright flash of light on the inside. This will result in a small flash at the muzzle but will also instantly charge tracer / glowing BBs on the way through resulting in tracer fire. Although visible in low light, most prominent effects are seen in darkness / night.
The unit runs on 3x AAA batteries. When using rechargeable batteries, you can use the included USB cable to charge them inside the silencer (having removed the outer shell, includes instructions). Be careful not to charge for more then 6 hours as that can overcharge the battery which is dangerous. Do not to charge non-rechargeable batteries and that is stupid and very dangerous.
The tracers come in two versions; the basic Blackside is a plain black silencer with the basic operation as mentioned above. The Flare version has milled slots in the casing to create a much more pronounced muzzle-silencer flash when firing. This is not realistic of course but it is very cool.
Batteries not included.