Permanent magnet hysteresis units can be configured as a clutch or a brake depending upon mounting. Torque is accurate and dependable because it is produced magnetically, not via friction. Torque is consistent over a given speed range. Because there is no wear, units have an extremely long life. Also since units are sealed, there is no concern about contamination. Each unit has an adjustable torque range that can be set by the user and since the units operate via permanent magnets, no external controls or power is required.