The Pro Series II Launch Controller is the ultimate launch controller for any single or clustered rocket! Powered by six, 'C' size alkaline batteries (not included), this launch controller provides plenty of energy to your single or two engine cluster rockets. The Pro Series II Launch Controller also features an alternative power source option for launching up to 10 rockets, a two-button arming and launch control system, audible continuity buzzer and 30 feet (9.1 m) of heavy-duty cable with four alligator clips.