Essential Tool for Seasonal Checks: This circulation pump rotation tester is invaluable at the end of the heating season, allowing users to verify the operation of circulation pumps and identify any potential blockages after extended periods of inactivity. Versatile Functionality: In addition to testing circulation pumps, this device can also check the operation of oil burner solenoid valves, making it a multi-functional tool for heating applications. Clear Indicator System: The built-in indicator effectively displays the magnetic field and rotation direction of most circulation pumps, providing immediate visual feedback on pump performance for quick diagnostics. User-friendly Design: Designed for convenience, the red and white screw rotates in sync with the pump, allowing users to visually confirm the direction of pump rotation easily. Compact and Portable: Small enough to fit on a key ring, this tester is an essential item that every plumber or heating contractor should have, enabling quick checks of pump operation and rotation direction. Product Name: Rotation Tester & AC Detector for Circulating Pumps Color: As Shown Material: Plastic Package Contents: 2 x Rotation Tester & AC Detector for Circulating Pumps Note: Light reflection and different displays may cause the color of the item in the picture to be slightly different from the real thing. The measurement allowed error is +/- 1-3 cm.