We stumbled across this amazing blog post from the Artist Formely Known as Scrambler Dan Strauss.
Some choice highlights in his review of the Scramble Grip Trainer:
Looks
Who gives a shit how they look?
and
As you can see when looped through correctly they were shockingly strong (the hard you pull the stronger they get).
There’s also a hilarious video. Dan loves to break stuff, that’s for damn sure, but he has some real trouble getting the grip trainers to split.
Buy them here! Scramble Grip Trainers