5x10 Metal Shielded Ball Bearings (10) 5x10x4 MR105-ZZ Includes Ten (10) High Speed Precision Steel 5x10 Ball Bearings. These bearings are perfect for any applications where 5x10x4mm MR105 ball bearings are required. Advantage Ball Bearings are perfect for a variety of applications including: RC Cars, RC Helicopters, Bicycles, Fishing Reels, Robots, Spinners, Inline Skates, Skateboards, Scooters, Tools, Machines, Vacuums, Electric Motors, Nitro Engines, Drones, Yo Yos, and more! Advantage Racing Product Bearings have been run by some of the fastest RC Car Racers in the world and have won multiple ROAR US National Championships. Over 250,000 bearings have been sold to satisfied racers all over the world! The Metal Shields provide moderate protection, but provides minimum resistance for maximum efficiency and speed.