This just showed up in the mail:

It is the Disc Brake System Analyzer from Innovative Products of America (IPA)

This is it in use on a caliper.

Under FCC rules I have to say IPA sent me the product to review. I will review the tool in the next few weeks on SafeBraking.com, but I will also use it to prove or disprove certian brake myths when it comes to brake drag and uneven  pad wear.

More to come