This is a 22mm isolating valve, which is classed as a "Full Flow" isolation valve, what this means is, the isolation valve has a been internal bore which allows more water to pass through the valve which means a chance of having a great flow, it is also used to turn off the supply of water from any fitting so that essential repairs can be carried out. This is more know for being a heavy pattern valve also. Screwdriver operated, brass, chrome plated isolating valve. Used in hot or cold water systems to isolate part of the system: avoids the need to drain down the whole system to carry out work. Compression fitting at each end. Available in singles and packs of 2,5,10 and 25 for bulk savings. WRAS Approved Sizes 22mm Max. Operating Pressure 8mm - 54mm = .