AFCO aluminum, mono-tube design, 9" stroke, big body 2.17" outside diameter, coil-over style (use 20135 kit), non-adjustable valving, user serviceable. 4 valve on compression and 8 valve on rebound. Fine tuning by adjusting gas pressure by Schrader valve, for chassis stability and driver feel. Compressed length 16.21", extended 24.15"