I own Alpha Bumpers and Pro Hex Rubber Dumbbells from Vulcan. The Alpha Bumpers seem great, although I can't comment on their durability yet since they're still new. The Pro Head Rubber Dumbbells are nice for the price, but I was a disappointed by how big the rubber seam on the handles was; it digs into my palm a bit when holding the dumbbells and would definitely cause blisters if I did high reps of anything where the handle rotated during the lift. I think I will be able to fix the problem with a file since the seam is only rubber, but annoying to have to do that for brand new equipment.