This is an original spare part by Tamiya, identified by the part number 50356. It is a 20T, 21T AV Pinion Gear Set, compatible with various Tamiya models including TA01, TA02, M02, M03, M04, M05, TT01, and TT02. Tamiya offers a wide selection of R/C spares, extras, and hop-ups such as wheels, tires, motors, and body shells for their radio control vehicles. This product is exactly as stated in the title.