The unit's pressure-balancing body ensures the pump's dual Pivotrol pumping mechanisms share loads equally. Vent-assist valves release pressure in the pump body during the exhaust stroke for faster filling and overall cycling. Two-thirds the size of units it replaces, the PTF4 has 4-in. inlet and outlet check valves.

Spirax Sarco Inc., 1150 Northpoint Blvd., Blythewood, SC 29016, (803) 714-2000,