Durable material: made of carbide alloy, strong and practical, not easy to rust, long time to use.Router bit set: containing bearings, set screws, lock ring,and hex key wrenches.Simple construction: nice operation. Provides much convenience to your daily woodworking.Small friction coefficient: precision bearing, specially designed for high rpm use on router bits.Powerful tool accessories: replace or repair the damaged or lost router bit bearings.Specifications:Product name: router bit setType: A, B, C, D, EMaterial: carbide alloyColor: silverSize(approx.):type (bearing) inner diameter x outer diameterA 4.76 x 9.52mm/0.19 x 0.37inchB 4.76 x 12.7mm/0.19 x 0.50inchC 4.76 x 15.9mm/0.19 x 0.63inchD 4.76 x 19.05mm/0.19 x 0.75inchE 6.35 x 12.7mm/0.25 x 0.50inchPackage Includes:(type A)5 Pcs x Upper Bearing5 Pcs x Screw1 PC x Wrenchor(type B)5 Pcs x Upper Bearing5 Pcs x Screw1 PC x Wrenchor(type C)3 Pcs x Upper Bearing3 Pcs x Screw1 PC x Wrenchor(type D)3 Pcs x Upper Bearing3 Pcs x Screw1 PC x Wrenchor(type E)5 Pcs x Lower Bearing5 Pcs x Bearing Ring5 Pcs x Screw1 PC x WrenchNote:1. Due to the light and screen difference, the item's color may be slightly different from the pictures.2. Please allow 0.5-2 cm differences due to manual measurement.