Botex Dr. RDM I DMX RDM Tester

I bought this for its RDM functionality. There are many smaller versions of RDM devices on the market. But for the price, this one works well. If you don’t use RDM very often or extensively, and you don't need to move around a lot on location, this device is good enough. I can imagine that if you work on location and need to set up RDM in many different places, you might be looking for a more compact version.
If money is an issue, then in my opinion, this is a good option.