This is the Team Associated RC10B7 3-Gear Gearbox Conversion Kit.
Includes:
(2) 3-Gear Gearbox Halves (ASC71215)
(4) Notched Differential Height Inserts (ASC71223)
(1) 3-Gear Gearbox idler gear 54T (ASC71216)
(1) RC10B7 Idler Shaft (ASC71217)
(1) Aluminum Arm Mount (C) (ASC71218)
(2) 3x8mm BHCS screws
(8) 3x16mm BHCS
(2) 3x8mm FHCS
(2) 10x15x4mm Bearings
3-Gear Conversion Manual