The Hydra-Cell Metering Solutions SM Series electronic solenoid metering pumps from Wanner Engineering are designed for reliable and economical chemical injection in multiple industries. They feature a hand-operated dial with stroke adjustment from 15 to 200 strokes per minute. Maximum discharge pressure ratings are from 58 to 217 psi depending on the model. The pumps feature a double-ball check valve to help ensure metering accuracy and reduce the possibility of water hammer. An anti-siphon check valve prevents clogging at the injection point and aids in priming the pump. An optional integral relief valve releases abnormal pressure automatically if the pressure exceeds the pump’s capability, protecting it from damage. All models are equipped with a protective secondary diaphragm. 612-332-5681; www.hydra-cell.com