Frequency Reader Counter is a wireless remote control testing device that can accurately detect and display the frequency of remote-controlled devices. The Frequency Counter test method is simple: bring the remote control device close to the frequency counter to accurately read the remote control frequency. The effective test distance is within 10cm. Type: 250-450MHz Frequency Reader Counter, Wireless Frequency Counter Features: - Portable frequency counter design - Suitable for use in electric door controller manufacturing, automatic door systems, and related fields - Equipped with a 4-digit display for clear reading results - Easy to operate and carry Effective Test Range: 250MHz to 450MHz Valid Test Distance: Less than 10cm Power Source: 9V 6F22 battery (Not included) Operating Voltage: DC 9V Standby Current: 40mA Operating Current: 51mA Dimensions (L x W x D): 9.3 x 5.8 x 2.4cm / 3.7 x 2.3 x 0.9 inch How to Use: 1. For wireless remote controls, place the remote in the sensing zone and press any key. The frequency will be displayed on the screen. 2. For infrared remotes or other transmitters, point the remote toward the infrared receiver (INPUT) and press any key. A red light indicates the transmitter is functioning normally. This wireless remote control detector is intended solely for testing and educational purposes. Users must comply with all applicable laws and regulations in their country. Not intended for illegal use. Designed for professional use in automotive repair shops, garages, workshops, and by automotive locksmiths. Color: Gray & White Material: Plastic Package Contents: 1 x Frequency Counter 1 x Battery Connector Note: Light reflection and differences in display screens may cause slight variations between the color shown in the image and the actual product. Measurement error allowance: +/- 1-3cm.