Similar to disc magnets, ring magnets are a thin flat design featuring a central hollow or cavity. Specifications for these types of magnets are measured by the outer diameter, inner diameter and thickness. Ring magnets are most often deployed on a spindle, axle, shaft or rod. Ring magnets in this context regulate at what mechanical threshold components subject to its magnetic field can move and how fast. Components expressing insufficient mechanical intent or pressure remain stationary. Housed in linkages mediating between motors, shafts and gearing assemblages, ring magnets assist in the control and expression of mechanical force. Ring magnets are often part of fail-safe devices, torque limiters or an overload clutch. These mechanisms are designed to protect motors and associated apparatus in jam or 'crash stop' event by returning equipment to a risk free state. Buy Rare Earth or Ferrite ring magnets!