DURABLE: This BSP (British Standard Pipe) brass tap and hose adaptor has connector sizes 1/2? & 3/4? and is ideal for outdoor use. EASY TO ATTACH: It has a handy wall plate elbow with a 15mm compression fitting with pre-drilled holes for wall attachment. COMPLIANT: Fitted with double check valves to prevent back syphoning and water contamination, it complies with Water Supply Regulations.