This is the optional Unassembled 3-Speed Transmission for the HPI Savage series. Provides higher top speed (top gear is 10% taller than stock) and more torque (low gear is 10% shorter than stock) Steel clutch holder and steel second and third gears for extra durability Factory pre-set shift point is also user-adjustable Compatible with all Savage trucks One 3-Speed Transmission for the HPI Savage with illustrated instructions, tube of threadlock, 2mm hex wrench, 1.5mm hex wrench #2 phillips screwdriver (DTXR0124), glow plug wrench with 8mm socket (HCAP2550) If Center Gearbox is needed, order HPIC5046 If Clutch Gear Hub is needed, order HPIC0778 44 Tooth Spur Gear is available separately, HPIC0754 jxs 5/05/05 ir/jxs &