Got news for ya....Fein was the company that invented the tool back in the early 80's to remove windshields from the '82 (and up) Audi 5000.
After that, Ford started installing windshields in their Taurus' ('86) in a similar fashion.
There was NO way to remove those windshields at the time except with a hammer and a chisel. So the tool made it's way to the US.
I owned one back in the early 80's when it was simply called a "Fein Knife" (Still is today by autoglass installers).
Only in the past few yrs did Fein start adding additional blades to it and start calling it the "Multimaster" which was then made available to the public.
So EVERY other company, ripped off Fein.