AFCO aluminum, mono-tube design, 7" stroke, big body 2.17" outside diameter, coil-over style (use 20135 kit), non-adjustable valving, user serviceable. 7 valve on compression and 4 valve on rebound. Fine tuning by adjusting gas pressure by Schrader valve, for chassis stability and driver feel. Compressed length 14.21", extended 20.15"