Integrated Design: Consists of a special circuit board, microcontroller, digital tube, high-precise distance measuring module, buzzer, and other components, highly integrated. Easy to Use: Simple operation, no programming required, can be used by simply plugging into the powersupply, no professional knowledge required. High-precise Distance Measurement: -SR04 high-precise module, built-in high-accurate distance measurement probe, stable distance measurement, measuring distance up to 4 meters, to meet most of the distance measurement needs. Real-time Display: Transistor-driven digital tube, the digital tube real-time display of the current distance to the obstacle, so that the user can real-time grasp the distance information. Alarm Function: Buzzer alarm function, when the distance is less than the alarm distance, an alarm sound is issued to remind the user to pay attention to increase safety. It can be used as the reverse radars of the car, and the alarm distance can be set by the buttons, applicable to a variety of scenarios. It consists of a special circuit board, microcontroller, digital tube, high-precise distance measuring module, buzzer, and other components, no programming is required, can be used by simply plugging into the powersupply. Built-in high-precise distance measurement probe, stable distance measurement, measuring distance up to 4 meters. Real-time display of the current distance to the obstacle, and with buzzer alarm function, it can be used as the reverse radars of the car, and the alarm distance can be set by the buttons, applicable to a variety of scenarios. Name:Distance Measuring Module Power supplying:5VDC or 3xAA battery (not included) Measuring ranges:0.01-4.00m Printed circuit board size:72x62mm/2.83x2.44in With housing size:89x77mm/3.50x3.03in Colour:Blue Material:FR-4+acrylic Package Contents: 1 * Distance Measuring Module 1 * Housing 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.