Exotek B6.4/B6.3 Brass "C" Block. This optional C block is constructed from CNC machined brass giving you an additional 24g of weight to the rear of the B6.4 and B6.3 platforms. This additional weight can help to plant the vehicle in lower traction conditions while also keeping the weight as low as possible. Overall this is an excellent and easy upgrade for your buggy. Package includes one brass C block.