Blue-White Industries FLEXFLO® A1N20A-7T A-100N High Pressure Peristaltic Metering Pump with Analog Timer for Chemical Feeders; 7/16" OD, 76.1 GPD, Polypropylene, 115V 60HZ, 50 PSI is well suited to metering chemicals that could foul heads with conventional check valves. Peristaltic pumps have rollers that compress the tube in aprogressive squeezing action. Blue-White’s superior FLEXFLO® peristaltic injectors have an impressive edge over the others. Only FLEXFLO® pumps feature Blue-White’s superior pump head and tube design. All FLEXFLO® Peristaltic Pumps are equipped with Blue-White’s exclusive patented tube failure detection system