Are you referring to the Agility Paddles?
If so, I love them. I have been using them for 2 years and I love how they keep me honest. If I get lazy, they fall off.
I have the agility paddles too. Love them. But I think you can also cheat with them. You can literally have your forearm pulling back at 20 degrees relative to the horizontal and they will stay on because there is enough pressure (I have caught myself cheating to lower the workload from the surface of the paddle):
Ive got these. The only thing I dont like is Im trying to angle down my reach before the catch and unless my reach is extended strait and above the water before the catch they get yanked off my hands.