Bones Swiss bearings are created by a standard that other bearings are compared. The Bones Skate Rated design and Swiss manufacturing are the optimal combination. These bearings have been time tested for over 20 years by professional skaters and are the most desired in the sport due to their speed and durability. Not to mention, a rubber single shield which removes to provide for easy cleaning and a lot less resistance when rolling. The materials, tolerances, and lubricant of the bearings provide for the best performance and durability.