ABEC-5 Ball Bearings 5x11x4 Stainless Steel Lot of 10 Bearings High Quality 10 bearings Stainless Steel Ball Bearings ABEC-5 quality, this is a popular size that could be used in many application that uses this size 5mm x 11mm x 4mm. Bearings are made of Stainless Steel and can rotate up to 52,000 rpm, each bearing has 2 metal shields to protect the bearing from dust or any possible contamination, also bearings are pre-lubricated with grease.