Coilover kit - BC Racing - External Reservoir - ER Series - Corolla AE86External Reservoir ER Series Coilover kit for Corolla AE86 BC Racings premium flagship coilovers are the external reservoir ER Series with separate compression and rebound damping adjustment. The ER Series coilovers bring with them the high quality and unique features seen on the BR and RM type but have the additional benefit of external reservoirs and the ability to allow the end user to individually adjust and set compression and rebound damping