SR3ZZ ABEC 7 SI3N4 Ceramic Shielded Bearing 3/16"x1/2"x 0.196 inch MiniatureSR3ZZ ABEC 7 SI3N4 Ceramic Shielded Ball Bearing 3 16" x 1 2" x 0. 196" inch Miniature SR3ZZ ABEC 7 SI3N4 Ceramic Shielded Ball Bearing. This is a popular size that could be used in many applications, the inner diameter is 3 16", outer diameter is 1 2" and the width is 0. 196". Each bearing has 2 metal shields to protect the bearing from dust or any possible contamination. The bearing is pre lubricated with grease. Item: SR3ZZ ABEC 7 SI3N4 Ball