Western Enterprises OPA Series Compact Click-Style Regulators Dial-in flow control. Hose barb outlet. Compact aluminum body with brass inlet chamber. Internal reseating relief valve protects against overpressurization. OPA series designed for pediatric, homecare, hospital and emergency applications Pack of 1 WARNING: This product can expose you to Lead, a chemical known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov - Lead