The new xcortech X3300W is one of the best control units available on the market! This includes a tracer unit, an AEG control system, and a control unit that is disguised as a PEQ box. This system measures ROF, BB velocity, Counts up shots, Counts down shots, Provides a total shot count, enables burst fire control on AEGs, displays AEG battery level and has a low AEG battery detect! Both the tracer unit and the control box are battery powered and both communitcate wirelessly. The control box is powered by 2 x AA batteries (not supplied), and the tracer unit is powered by 4 x AAA batteries (not supplied)