Bag of ten 2-inch steel rollers with 10-ball bearings. Steel wheels roll well and they are tough, but they are noisier than nylon, so keep that in mind When your garage is attached to the house. These come with a 7/16 inch shaft and you pick your stem length at checkout: 4 inch for light commercial setups, 7 inch for standard residential, or 9 inch for extra-tall doors. Match the stem to your hinge number. A #1 hinge uses the shortest stem, and it goes up from there. Ten rollers is usually enough for a standard two-car door.