Mersen's patented TPMOV® (Thermally Protected Metal Oxide Varistor ) eliminates common destructive failure modes associated with standard MOVs. Comprised of a voltage clamping device and a disconnecting apparatus that monitors the status of the metal oxide disk inside the TPMOV, the device is securely disconnected in the event of an overvoltage by an arc shield. Upon failure, the TPMOV is also equipped with a visual pin indicator as well as a normally open microswitch providing remote indication, if applicable. 420 Volts Micro and Short Leads series.