Ring magnets are measured by their outside diameter x inside diameter x depth.
The outside diameter of a ring magnetic disc refers to the distance between the two widest points. The outside diameter ranges from 1mm (0.039″) to 256.5mm (10.1″).
The inside diameter of a ring magnetic disc measures the diameter of the hole can can range from 0.5mm (0.02″) to 121mm (4.76″).
The depth of a ring magnetic disc is the distance between the two magnetic faces and can range from 0.5mm (0.02″) to 44.45mm (1.75″).
The magnetic pull of ring magnetic discs ranges from 0.018kg (0.04lb) to 165kg (363.76lb).
