The XTM Racing Sure Start electric starter was designed to start the big block engines that other starting systems have a hard time with. With its large 750 size motor and ballraced spiral worm gear reduction drive, Sure Start has no trouble turning over those popular high compression engines fitted to today’s vehicles! This easy use, high torque starting system requires a 7.2V battery pack (not included). For best results, ensure you use a quality battery pack. Suitable for use with: XTM18~28, OS.15~30, SH12~28, Force .15~.46, HPI .21~.25, GS.25, Mach .26, Sportwerks .28