RPM Caster Blocks for the Traxxas Slash 2wd, Nitro Slash, e-Rustler & e-Stampede are the final link in for a complete, bulletproof front suspension from RPM for these trucks. RPM Caster Blocks are redesigned to slim down unnecessary bulk while improving strength and durability in this heavily impacted area. These are stock replacement items. No additional parts or modifications are necessary to mount a set to a vehicle. RPM Caster Blocks are molded in our trademark blend of ultra durable and super strong nylons and backed by the best breakage **in the R/C industry. Each package contains one left side and one right side caster block.