These wheels are amazing. I needed strong casters to support a sturdy workbench that needs to move around the garage and slide out of the way so I can park my car there when I'm not working. These roles are perfect for that. The floor in my garage is covered in sawdust and wood shavings, not to mention the occasional nail or screw, and the wheels roll around with no problem. The locking feature is really handy because when it's on, the workbench is as solid and motionless as if there were no wheels on its feet. I paid $20 for a set but even at $30 they would still be a great value. The wheels themselves are actually 5 inches in diameter and the overall wheel height is 6 inches. Mounting holes are for 3/8" screws. I used 1" screws with pilot holes and had no problem getting the wheels loose. My woodwork can result in sawdust getting into the locking mechanism and possibly contaminating it. I haven't had any issues with it yet though, and I think a shot of compressed air will easily fix it. I'm building another portable miter saw stand and plan to use these casters for that stand as well.