The ER series is BC’s newest and most advanced coilover design to date. ER series coilovers feature large external front and rear fluid reservoirs with separate adjustments for rebound and compressions. An advanced twin piston shock design separates the ER series from rest of the pack, with pistons in both the shock body and the external reservoir for pinpoint accuracy. The external reservoir system holds dampening fluid separate for the main assembly, allowing more precise and repeatable shock feedback without overheating. The BC Racing ER series coilovers represent the absolute ultimate in suspension versatility and adjustability for the serious racing enthusiast.