I would also support/recommend the use of the FastArm. My 2014 son is a catcher has had it for about 5 weeks now and has seen great improvement in pop times and success in caught stealers. Uses it in a training routine and in a pre-game warm up routine.
My opinion thus far is that the improvements thus far are from improving his mechanics not necessarily strength. He does long toss and the schools strength and training program therefore we'll likely not be able to ever say strength is from one thing or another but a combination of them all.