Ball Bearings 6908ZZ 40 mmx 62 mm x 12 mm One Bearing One Ball Bearings the inner diameter is 40, outer diameter is 62 and the width is 12, this is a popular size that could be used in many applications, Bearings are made of Chrome Steel, bearing has 2 metal shields to protect the bearing from dust or any possible contamination, also bearings are pre-lubricated with grease.