RPM 73442 ECX Torment 2WD, Ruckus 2WD, Circuit 2WD and Boost Heavy Duty Caster Blocks, Black Designed to increase durability Replaces weaker stock components, check for full parts compatibility Made by RPM R/C products, a United States based company where resources are sourced from American producers Replaces the caster blocks for stock ecx #234000 Fits 2WD versions only