E.R. Wagner Stem Caster, Swivel, Polyurethane on Polyolefin Wheel, Precision Ball Bearing, 450 lbs Capacity, 3" Wheel Dia, 1-3/4" Wheel Width, 3-7/8" Mount Height, 1/2"-13 Stem Dia, 1-1/2" Stem Height

On the job, on the money. They are exactly as described, and roughly 1/4 the price of similar stem casters. They're as tall as I imagined (I went bigger than the casters I replaced), but they're stout, roll easily, swivel easily, install with a little bit of grunt (meaning the shouldn't fall out any easier than they "fell" in). All in all, very pleased. I haven't really put them through an endurance test or doused them with harsh chemicals or anything, but I imagine there wouldn't be any surprises there. If you do something you expect might destroy them, I would go ahead and expect it to destroy them. For the price, you have a hard time expecting them to be up to NASA specifications...though they seem perfectly competent.