6801-2RS Sealed Ball Bearing 12mm x 21mm x 5mm One Ball Bearing 6801-2RS Sealed Ball Bearing, a popular size that commonly could be used in many RC wheel and motor applications that requires this size 12mm x 21mm x 5mm, each bearing has 2 Seals to protect the bearing from dust or any possible contamination, also bearings are pre-lubricated with grease.