Stenner Classic Series metering pumps are self-priming, and the 3-point roller assembly provides a positive 2-point seal on the pump tube at all times. This eliminates the need for anti-siphoning valves and diaphragms. The patented mechanical feed rate control (adjustable models) allows the pump’s output to be scaled from 5% to 100% with the simple turn of the dial. Injection valve, Foot valve and Tubing included with all pumps.