Size Information-the roller skate wheels is 58mmx39mm, the inside bearing inner diameter is 8mm, outer diamter is 22mm 608RS High Speed Bearings-good bearings are that allow your wheel to a long time with little effort 95A Hardness with Lines-ensures durability and smooth when rolling, the lines on wheels offers great grip and stability PU material Wheels-wear and these roller skate wheels work for casual indoor skating or competitive skating How to Install-just remove the old wheels and put the new wheels on, easy to install and suitable for Jam, , Speed, Session skating style A good wheels offer you better experience during roller skating. 95A Wheels 608RS Bearings Material:PU+PP colour:Black+red+silver Package Contents: 4 x pulleys 1 x wrench Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.