Muchmore Premium Racing ball bearings
Muchmore introduce their Premium Racing ball bearings in a range of sizes. Coming with a protective rubber shield on one side and a drag-reducing metal shield on the other side the bearings will offer exceptional protection against the elements while improving the drivetrain efficiency compared to all-rubber sealed ball races at the same time. The bearings come pre-oiled using high-temperature resistant oil and they are available in five different standard sizes with the 5x10x3mm offering being the only all-metal seal one.
Source: Muchmore [muchmoreracing.net]