Changed my 3-in casters out to 5-in. The rubber had gotten hard on the harbor freight 3-in casters, and the side of the rubber had even broken off of one. This material seems to be more urethane-like. Rolls easier too. At $3 a piece I didn't expect much from the harbor freight casters.... These new ones came off of Amazon under of course Chinese as well, $33 for a set of four