I bought this item cheap and saved about $4 per wheel compared to the wheels I bought from HD. However when I got these things on my mobile Fixed cart and fixed the wheels I was very disappointed.I mean the wheels are good,rubberized and big but the bearings that attach to the mounting plate are loose so not suitable for my mobile cart.If you don't use them need to lock up, do so, but if you're looking for a solid stable mobile base (when the wheels lock up) go for the HD and pay $12 per wheel - they're reliable.