ABEC-5 Ball Bearings 6x13x5 Stainless Steel and Ceramic Balls Lot of 10 Bearings 10 Stainless Steel Bearings with Ceramic Balls ABEC-5 quality, It is a popular size that could be used in many application that uses this size 6mm x 13mm x 5mm, each bearing has 2 metal shields to protect the bearing from dust or any possible contamination, also bearings are pre-lubricated with grease.