This is an optional RPM Rear Shock Tower, and is intended for use with the Associated SC10 and T4 trucks. RPM Shock Towers for the SC10 & T4 are designed to improve the structure and durability of these awesome racing trucks. The I-beam shape found along the tops and sides of the shock tower provide some serious strength and rigidity while the chemical make up of RPM's proprietary blend of nylons provides unmatched durability. The end result – a new shock tower design that will rigidly support the rear shocks while allowing the part to survive under extreme crash situations.