It is mainly used to measure the speed of outdoor moving objects on the back. It has a wide range of application scenarios, is simple to operate, and is easy to use. This product has a built-in lithium battery, which can be used continuously for 4 hours when fully . This product can provide you with the following data. (1) Fastest speed (data be locked) (2) Real-time speed (real-time update) How to use: 1. Place the speedometer on the test object, install it firmly, with the module facing upward and not blocked by metal objects. Turn on the power switch and wait for the module to search for stars. When the number of satellites reaches more than 7, it means that the speed measurement can be started. When the number of satellites reaches 7 or more, speed measurement can be started. When searching for a new location for the first time, you need to wait for more than 3 minutes. (The greater the number of satellites, the more accurate the be) 2. The product is equipped with a type-c charging interface. The red light turns on when charging and the blue light turns on when fully . 3. Regarding the use of the reset button. There are two methods for data reset. This product does not have a data storage function. The data needs to be reset when the speed is measured for the second time. Due to the characteristics of GPS, data drift and other phenomena occur. The data not be cleared after clearing. In addition, after the device starts to power on, the instantaneous action It also lead to changes in data. Weight:43.5 grams Colour:Black Material:ABS Size:67x33x21mm Package Contents: 1 * GPS speed detector 1 * data cable 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.