1HIGH ACCURACY: This digital servo tester has high accuracy, and the output signal can be accurate to 2us, which is very versatile. 2ADJUSTABLE PULSE WIDTH: Using a rotatable potentiometer can decrease or increase the width of the output pulses of the digital servo tester. 3CAN CONTROL MULTIPLE DEVICES: The digital servo tester can test and control 4 servers at the same time, changing the test mode as needed. 4SMALL 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. 5PLASTIC SHELL: The housing of the digital servo tester is made of plastic, which is scratch resistant, drop resistant and has a long service life. Item Type: Digital Servo Tester Material: Plastic and electronic components Color: Black Product Size: Approx. 75 x 38 x 16mm / 3 x 1.5 x 0.6in (without knob) Output Signal Width: 800-2200us Key Selection (Note: key switch function, cycle mode): 1. S-1 Manual Mode 2. S-2 Bit mode (neutral) 3. S-3 Auto Mode (Auto) Applicable: RC remote control helicopter steering gear 1 x Digital Servo Tester