Traxxas TRX-4M Brass Steering Blocks. These optional brass steering blocks are an excellent way to upgrade your TRX-4M rock crawler. Constructed from brass these are stronger than the stock plastic parts and add weight low on the chassis for improved crawling stability. With brass construction these add 7 grams of additional weight to the front of the vehicle. Package includes one left side steering block, one right side steering block and mounting hardware.