14x21x4 Ball Bearing Shielded Non-Standard ID 14mm x OD 21mm x 4mm14x21x4 Ball Bearing Metal Shielded Non Standard ID 14mm x OD 21mm x 4mm Ball Bearing, a standard bearing size with dimensions commonly used across many industries: 14mm x 21mm x 4mm. Made from high strength chrome steel for durability and performance Bearing has 2 Metal Shield to protect the bearing from dust or any possible contamination. Double Shielded Ball Bearings Size: 14mm x 21mm x 4mm Deep groove ball bearings Material: Chrome Steel Shield