Features: 1 to 999.9 meters per second projectile with accurate speed. Speed measurement, energy measurement, speed energy, browsing records and checking averages. Large effective induction area, easy to use, high sensitivity. Mainly used to learn and experience the high-speed data processing ability of single chip microcomputer, which can measure the flight speed of various projectiles. Apply for table tennis, badminton, bow and for arrow, physical acceleration experiment, projectile free fall experiment, for NerF toy speed measurement, children's soft toys, etc. Specifications: Material: Aluminum Size: 330x80mm/13x3.15in Type: single speed meter/bracket/ 1 set speed meteroptional Voltage: for DC 6V Batterynot included: 4 x AA batterynot included Working Temperature: -30°C - 60°C Accuracy: test error 0.5 Measuring Range: 1-3000 for M/SFPS range 30-9000 Package Includes: 1x Speed Meter or 1 Set Speed Meter note: Please allow 1-3cm error due to manual measurement. pls make sure you do not mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item.