The Mastercool 58203 2/3-Valve 3/8 in. Ball Valve Aluminum Manifold features an exclusive 3/8 in. ball valve design in which the full 3/8 in. bore all the way through the block increases flow over standard block designs. The ball valve rotates 90° between two Teflon washers which allows for very little effort required to turn even when under pressure. The valve opens and closes quickly with only a quarter turn required. The visual knob position quickly indicates if valves are open or closed, and the 3-1/8 in. gauges are color-coordinated for multi-refrigerant recognition.