One of BC Racing's most advanced models yet is the BC Racing ER Series coilover. The ER features large external front and rear reservoirs, separate rebound and compression adjustment, and a twin piston design for maximum performance and tuning. The external reservoirs displace a higher capacity of oil allowing for cooler operating temperatures over an extended period of time. The external reservoirs also house the secondary piston which allows for the adjustment of compression. This is the perfect coilover system for the person who wants to fine-tune their setup using the separate, 30-click, rebound and compression tuning knobs. The ER Series damping (compression and rebound) can be adjusted with your fingers, meaning there is no need to carry additional tools to dial in your setup at the track.