Ceramic Disk Valve

The older style of faucet needs two full turns of the handle to activate the flow but low friction ceramic valves allow the faucet to operate with just a quarter turn of the handle.
Ceramic disk valve. Each time you use one of our faucets two discs control water flow by gliding back and forth in an airtight seal that prevents leaking and ensures a super smooth operation. Hose guide mounting brackets. Ceramic disc valving is an innovative water control system found in each american standard faucet. Hose guide mounting brackets.
Source : pinterest.com