It is a remote control frequency tester, which can accurately test the remote control frequency with clear display. When using the remote control, you can easily adjust the exact frequency you need. Working current: 51mA Test coverage: 250-450MHz Test distance: 10cm/3.94in Working voltage: DC7.5-12V Test accuracy: +-1MHz Battery recommendation: 9V laminated dry battery (not included) Test : As long as the remote control is not more than 10cm close to the tester, the remote control can be accurately tested. Applications: Electric door controllers, automatic doors and other anti-theft alarm controllers, remote controls, electric locks, garage door remote controls, door guards, etc. Colour:As Shown Material:plastic Package Contents: 1 X Frequency Detector 1 Cord(not including power supply) 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.