[ MATERIAL]Made of high carbon chrome ball bearing steel for excellent mechanical performance.; [SMOOTH ]Fine polished surface ensures great smoothness in movement.; [SPHERICAL RACEWAY DESIGN]Features a roller way type with a spherical raceway for smooth .; [Stable AND WELLCRAFTED]Expertly crafted with good quality materials for excellent durability.; [PRECISE ]Inner diameter of 8mm, outer diameter of 30mm, and thickness of 14mm for accurate tracking.

What's in the box
1 x Bearings