ToolkitRC ST8 Advanced Servo Tester, Driver, Analyzer (PWM/PPM/S.Bus)

Works great at centering servos. No need for an esc and shows you end points and center with more precision.

This tool tester really works great

Great tool to have in testing servos before install.

Mine had bent connection pins, was able to bend back myself, no quality control

I've been quite impressed with the ST8, so far :) It's relatively easy to configure and use (once you know how... see below) and appears to be well built. The instructions included with the device are not great, however, so I'd recommend the 3rd party instructions provided by Peter Scott, at:

https://intellog.com/assets/pdf/rcsd-2021-03-toolkitrc-st8-servo-tester.pdf

There certainly are cheaper servo testers on the market but none of them, to my knowledge, provide the flexibility and feedback provided by the ST8.