Brand New SPEED TECH Single Training Version Wireless Laser Timer Skating Track and Field Running for Sprints Bike Motorcycle Racing Infrared Induction Timing Manufacturer model: Precise timing of a single person moving from the starting point to the end point Effective laser distance: 0-8m , Wireless communication distance: 500m Rated voltage and current: 5V 2A , Please use qualified power bank(The device needs three power banks) When testing at close range, please ensure that the laser sensor and the display screen are 2 meters or more away from each other to prevent co-channel crosstalk between the antennas and cause communication errors. Simple operation, plug the power cord into the USB port of the power bank, tap the reset button on the side of the screen for 1s to reset and start using