ALUMINUM CASTER BLOCKS: Traxxas aluminum caster blocks improve the appearance, ruggedness, and control on the your Traxxas model. In addition to the strength and precision of the machined billet 6061-T6 aluminum, the red, blue or green anodized caster blocks feature a high-contrast laser etched TRX logo. Simple bolt-on installation that anyone can perform inspires confidence for future upgrades.