I bought these rolls to build a sewing trolley on wheels to keep in my spare closet so I don't have to keep the sewing machine out of the house all the time. but it is still very easily available. The sewing machine is upstairs, supplies are on the shelves below. I just take it out of the closet, put it in and sew. You can use the same concept for art supplies, printer/fax etc. Carts range from $50 to $100, but using four of these casters and a $19.99 wire frame, I built a cart for about $35 (and under 5 minutes). work great and roll smoothly. Home Depot (where I bought the shelves) DOES NOT sell the right size threaded rollers to fit their shelves (perhaps to force you to buy an expensive trolley?), but they are the right size and screw on perfectly. The problem is that I bought four wheels with brakes and they accidentally sent me 3 wheels with brakes and one without. You shouldn't send it back for an exchange, because the car won't go anywhere with the other three wheels.