* Essential tool for seasonal inspections: This circulation pump rotation tester is very useful at the beginning of the heating season, allowing users to verify the operation of the circulation pump and identify possible blockages after a long period of inactivity. * Versatile: In addition to testing the circulation pump, the device can also check the operation of the oil burner solenoid valve, making it a versatile tool for a variety of heating applications. * Clear indication system: The built-in indicator can effectively display the magnetic field and rotation direction of most circulation pumps, instantly displaying the pump's performance for quick diagnosis. * Humanized design: The convenient design, the red and white screws rotate synchronously with the pump, allowing users to easily and intuitively confirm the rotation direction of the pump. * Compact and portable: This tester is small and portable and can be hung on a keychain. It is a must-have tool for every plumber or heating contractor to quickly check the operation and rotation direction of the pump. Color: As shown Material: plastic Package Contents: 2 testers Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.