13 x 19 x 4 Ball Bearings Rubber Sealed One Bearing 13 x 19 x 4 Sealed Ball Bearing, this is a popular size that could be used in many applications that uses this size 13mm x 19mm x 4mm. Each bearing has 2 Rubber Seals to protect the bearing from dust or any possible contamination, also bearing is pre-lubricated with grease.