The 39T option provides slightly taller gearing

Left and right tire set

Combine with Pro-Line’s Vice CrushLock 2

Part number: PHB2S520050BAN

Arrma ARA210003 4X4 Transmission Upgrade Set ARRMA BOOST Battery Tester The 39T option provides slightlyArrma ARA210003 4X4 Transmission Upgrade Set ARRMA BOOST In The Box (1) ARRMA 4x4 Decal Sheet (2) Universal Joint front slider driveshafts (1) Assembled composite differential (1) Differential Yoke (1) Hybrid Aluminum and Composite Input Gear (1) Short Center Driveshaft to suit GRANITE & VORTEKS 4x2 BOOST Models (1) Long Center Driveshaft to suit SENTON 4x2 BOOST Models (1) Instruction Manual Needed to Complete (1) ARRMA GRANITE, SENTON, or VORTEKS