1、These miniature bearings are made of high quality steel for low noise and long service life 2、They are double rubber sealed to avoid contaminants entering and save lubricant 3、Bearings have a3mm inner diameter, a 10mm outer diameter, and a 4mm thickness 4、These are great for 3mm shaft/rod projects such as mechanical equipment,electrical instruments, toys. 5、There comes total 10 pieces miniature bearings which you may use for many different projects Features: These miniature bearings are made of high quality steel for low noise and long service life. They are double rubber sealed to avoid contaminants entering and save lubricant. Bearings have a3mm inner diameter, a 10mm outer diameter, and a 4mm thickness. These are great for 3mm shaft/rod projects such as mechanical equipment,electrical instruments, toys. There comes total 10 pieces miniature bearings which you may use for many different projects. Specifications: ISO Certificate ISO 9001:2008 Dimension ID (Inner Diameter): 3mm OD (Outer Diameter): 10mm Thickness: 4mm Material Chrome Steel Qty 10 PCS ABEC Tolerance Codes ABEC 1 Closure codes 2RS  (Two side rubber seals) Lubrication Wide Temperature Range: - 20℃to 120℃ Basic Load Ratings Cr   KN = 0.64 Cor KN = 0.23 Vibration Level Z1  (P0) Package Includes: 10 x Bearings