There was a bearing noise in my window air conditioner fan so I ripped it apart to check. I worked in an electric motor repair shop, so I had a little advantage in repairs. I ordered them, reassembled them and everything is fine. For people complaining about camp markings, here's a little lesson. The 608 model is exactly the same size and quality as the 608z, 608ZZ or 608RS. Some bearings only have a Z as the only difference between the 608z and the 608zz is that the 608z only has a shield on one side while the 608zz has a shield on both sides. Model 608 is unshielded and Model 608RS is a sealed bearing.