These magnetic discs can be used with our micro metal gearmotors with extended motor shafts as part of a quadrature encoder system that offers 12 counts per revolution. They are 2 mm thick with an outer diameter of 7.65 mm and an inner diameter of 1.0 mm. Appropriate Hall Effect sensors, such as those in our magnetic encoder pair kit with top-entry connector for micro metal gearmotors, are required to complete the system. These discs are bulk-packaged and must be ordered in multiples of five.