A chief advantage of using eddy current dampers is that there is no contact between the damper and the damped objects and thus there is no risk of hysteretic noise caused by mechanical friction. A possible drawback of using eddy current dampers is direct transmission of the damper motions to the mirror motions through the magnetic field couplings, since most mirrors in the interferometer possess permanent magnets for actuators. Suspension systems with eddy current dampers have been developed for TAMA [48] and their effectiveness has been demonstrated.