Features: Essential for seasonal maintenance, this compact circulating pumps tester quickly diagnoses pumps operations and detects solenoid functionality in heating systems, serving as a versatile double purpose diagnostic tool. Featuring a built in magnetic field indicators and color coded rotating screws, for precise troubleshooting. Designed for professional plumbers, HVAC technicians, and heating contractors requiring reliabled equipment to verify systems readiness during pre season inspections. Ideal for detecting pumps blockages after prolonged downtime or validating electromagnetic performances in boilers, radiators, and oil fired heating units. Its lightweight plastic metal construction with keychain ready portability ensures effortless storage in toolkits, making it indispensable for on site diagnostics across residential and commercial heating setups. Specifications: Size: main body 50x16mm/1.96x0.62inch Weight: 15g Component:Plastic, Metal Package Includes: 1pcs Heating Pumps Rotation Checker note: 1.Please allow 1-2cm errors due to manual measurement, make sure that you donot mind befores you order. 2.Due to the differences between different monitors, the picture may not reflect the actual color. Thanks for your understandings.