Part number: # 108928  Released: Apr. 11, 2013 Alu Adj. Shim for 1/10 Off-Road Alu Set-Up - XRAY XB4 (2) Description · Photos (2) · News (1) · (click to enlarge) Aluminum shim fits on the rear wheel axle, and the set-up system leans against the shim. For use with XRAY XB4 or any off-road car on which the set-up system cannot be inserted on the non-threaded part. The set-up system will then sit properly on the threaded area of rear wheel axles only. Set of 2.