Stenner Feeder Fixed Head 10Gpd 25 Psi Max 120VStenner Pumps 45MFL2 fixed rate chemical feeder is built with two detachable components: the motor and pump head. Outputs are dependent upon the rpm of the motor gears and the size of the peristaltic pump tube. The fixed rate pump has no output adjustment. All Stenner metering pumps have a 3point roller design in the pump head, which acts as a check valve to prevent back flow, siphoning, overdosing and loss of prime The motor's output shaft rotates at a fixed rpm which drives the roller assembly within the pump head. The chemical solution in the pump tube is captured between the rollers as they rotate and compress the tube. As the rollers advance, the squeezed tube section regains its original form and generates a vacuum, creating the selfpriming feature that delivers a constant flow unaffected by the outlet pressure Features-Positive displacement pump-3point roller design assists in antisiphon protection-Pump head requires no valves, allows for easy maintenance-Selfpriming against maximum working pressure, foot valve not required-Pump does not lose prime or vapor lock-Pumps offgassing solutions and can run dry-Output volume is not affected by back pressure-Spare 50 GPD tube included-Easy to change pump tube lubrication is not required-Pump tubes and pump heads interchange between models-Models tested by WQA to conform to ANSI/NSF STD 61-Models tested by ETL to conform to ANSI/NSF STD 50-All pump accessories included allow a fast and easy installation-Fixed rate of 10 GPD, ideal for spas and smaller pools-110 VAC supply, 25 PSI