Which a tuned engine for use with Star-Unit Series releases, and can use Item 55105 or Tamiya R6/AA/UM3 batteries as an electrical supply. See below for appropriate pinion gears.
Compatible Chassis
SW-01*1 & T3-01*2 Chassis
*1Compatible pinion gear: product 54228 (26T just). Use with products 54834, 54857 and 54876.
*2Compatible pinion gears: items 50354 (16T just) and 50355 (18T just). Utilize with Things 54900 and 54928.
*The formal Tamiya R/C Parts Matching List has a good amount of information regarding framework befitting Tamiya free and Hop-Up option elements.