The H-Street Speed Bearing is a high quality speed component that is made of hardened steel, using Titanized technology and shielded on one side for maximum speed. They are rated ABEC 7 and come complete in a tin can with spacers and washers to ensure a quality ride.
Use spacers for softer wheels. For harder wheels, they are not necessary, assuming you insert the bearing and attach the wheels to your trucks correctly, which is best done by tightening the wheel nut a medium amount, so that the bearings are seated properly in the wheel, then backing off the nut, about a half a turn, so it places minimum pressure against the bearing race, even having a tiny bit of “play” in the tightness.
For best performance, also use one or two drops of a high quality lubricant, such Bones Speed Cream or alternatively, you can use sewing machine oil. Do not over lubricate as that will harm performance.
The tin can is also a handy parts or other stuff stash container.