Hobbyking S1 servo tester is specifically designed to accurately measure the servo speed and helps to understand the overall performance.Hobby King S1 is the first integrated servo tester in the market which allows you to measure speed, duty cycle, travel linear & range also receiver output signal and frequency. Specifiaction: Input voltage: 8~12V (2S lipo or 9V 2A DC power supply) Output voltage: 5V Output current: 1A Accuracy: 1us +/- 10% Weight: 21g Size: 69x33x11mm Operating temperature: -10~50°C Included; 1 x Servo tester 1 x Gyro sensor 1 x voltage regulated multi-functional servo extension wire