MIB Series spherical bearing. Made with low carbon steel race. With inner diameter of 5/8". Includes PTFE race lining. QA1's MIB and MIB-T Low Carbon Steel Series spherical bearings offer more wear surface than a traditional COM bearing, extending the life due to the increased race width and diameter. An optional self-lubricating PTFE liner is also available with these spherical bearings (MIB-T Series).