This is the GPM Racing Traxxas aluminum gear adapter with steel 32 pitch 56T spur gear & 19T motor gear for Slash 4X4 vehicles.
Spur gear and motor gear made by hardened steel match with aluminum adapter to improve the power output to be more consistent.
(56T with 13T=1:4.307)
(56T with 14T=1:4.000)
(56T with 15T=1:3.
(56T with 16T=1:3.500)
(56T with 17T=1:3.294)
(56T with 18T=1:3.111)
(56T with 19T=1:2.947)
(56T with 20T=1:2.800)