This is the optional 1.5° Aluminum Rear Stub Axle Carriers from Traxxas.

Features:
Machined aluminum construction
Anodized orange in color

Includes:

(2) Aluminum Rear Stub Axle Carriers
(2) 3x3mm Set Screws
(2) 3x12mm Flat Phillips Head Screws
(2) 3x31.5mm Pins
(6) 6mm E-Clips

This product is compatible with the following Model(s): Rally Brushless 4WD TQI (74076), Slash 4x4 RTR TQI (68086-1), Stampede 4x4 w/2.4G (67086-1), Nitro Rustler w/TQ Radio (44094-1), Nitro Slash 2WD TQ 2.4 Radio (44054-1), Nitro Sport SE 2.4 RTR (45104), Nitro Stampede RTR w/Radio (41094-1), Slash 4X4 Platinum Edition (6804), Slash 4x4 Ultimate Combo SC (6809L), Stampede 4x4 Electric 2.4GHz (67054), Telluride 4x4 Electric Extreme Terr (67044)