20Pcs V623ZZ V Groove Ball Bearing Pulley Wheels Roller Shape Wheel for Rail Track Linear Motion System 3x12x4mm

【High Quality】These bearings are made from high quality carbon steel for durability, with good performance and long service life. 【Double Shield】They are double shielded to avoid contaminants entering and save lubricant, more practical, can bring you more convenience. 【V Groove】These ball bearings is compact design, easy to carry and store, with 1.4mm deep V groove that generally ride on a rail or track. 【Wide Use】These are specialized bearings that are used in many linear motion systems, easy to use, can improve work efficiency, save time and energy. 【Package】There comes total 20 pieces bearings which you may use for many different projects.