This is the optional Generation 3 54T Slipper Unit from Robinson Racing for the Traxxas Slash 4x4. FEATURES: Steel and aluminum construction INCLUDES: One High Performance Slipper Kit with: One 54T Spur Gear Aluminum Back Plate Hex Slipper Pad One 7x13mm Bearing One Aluminum Spacer One Brass Bushing, RRPC7852 REQUIRES: Installation on the vehicle SPECS: Tooth: 56T Outer Diameter: 44.5mm (1.75") Inner Diameter: 5mm (0.20") lmm 04.30.10 ir/jxs