These are the best bearings that I have tried! Penny must have some secret formula or something. i've tried bones swiss, bronson G2, bones reds, 90's german bearings (you older skaters will know what I'm talking about), and maybe some others. But penny bearings maintain their speed the best and don't have any play in them. I skate far and fast! I just pop the shields off with the bearing still in the wheel and clean them with carburetor cleaner and grease them with white lithium grease every 20 to 30 miles. They just keep going better than the other ones in my five other boards. Smooth as glass! Hillbomb after hillbomb! Thanks, Penny!