These small testers are great for setting up new planes, they save a lot of time. I just bought this one and it has three functions: it centers the servo, allows you to manually move it end to end, and the sweep function automatically moves the servo back and forth until you stop it. It has a connection for up to 3 servos to test/set up at a time. I really added this to my recent Hobby King order since it was cheap and I wanted to see how useful it really was; it was $7 very well spent!

http://www.hobbyking.com/hobbycity/s...idProduct=8296