Feature:1. HIGH ACCURACY: This digital servo tester has high accuracy, and the output signal can be accurate to 2us, which is very versatile.2. ADJUSTABLE PULSE WIDTH: Using a rotatable potentiometer can decrease or increase the width of the output pulses of the digital servo tester.3. CAN CONTROL MULTIPLE DEVICES: The digital servo tester can test and control 4 servers at the same time, changing the test mode as needed.4. SMALL AND PORTABLE: The digital servo tester is small in size and easy to carry with you. It can test the steering gear of your RC helicopter anytime, anywhere.5. PLASTIC SHELL: The housing of the digital servo tester is made of plastic, which is scratch resistant, drop resistant and has a long service life.Specification:Item Type: Digital Servo TesterMaterial: Plastic and electronic componentsColor: BlackProduct Size: Approx. 75 x 38 x 16mm / 3 x 1.5 x 0.6in (without knob)Use Voltage: DC 4.8-6VOutput Signal Width: 800-2200usKey Selection (Note: key switch function, cycle mode):1. S-1 Manual Mode2. S-2 Bit mode (neutral)3. S-3 Auto Mode (Auto)Applicable: RC remote control helicopter steering gear.Package List:1 x Digital Servo Tester