This might be a tuned motor for use with Star-Unit Series releases, and will 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: Item 54228 (26T just). Utilize with Items 54834, 54857 and 54876.
*2Compatible pinion gears: Items 50354 (16T just) and 50355 (18T just). Utilize with Items 54900 and 54928.
*The official Tamiya R/C Parts Matching List has many information about framework compatible with Tamiya free and Hop-Up choice components.