Oil-16pk-8mm This bearing contains 8 balls instead of the traditional 7 which has many advantages. Load is spread out evenly, greater load capabilities while turning. Gives the ability to skate into turns harder with speed.
What is ABEC? Annular Bearing Engineer's Committee. This committee determines the ratings for each bearing. The ABEC rating system includes grades 1,3,5,7 and 9. The number determines how much "roll" the bearing has. The higher the number, the longer it will take for your wheel to stop spinning after you stop pushing.
Do I need 7mm or 8mm? Look at the stamping on the shield of your existing skate bearing. Most will be stamped with 608, this means you have 8mm. If it is stamped with 627, you have a 7mm.
If your bearing can slide a pencil its 8mm if it can't its 7mm