Chauvin Arnoux Metrix MX 604 [MX0604] 50V / 500V DC Insulation Tester. The Metrix MX604 surge arrester and megohmmeter enables to test easily and quickly without any risk, between 0 and 600 VDC. A support module connects to the instrument and allows the dismantled surge arresters to be inserted for the tests to be carried out. The MX604 enables the insulation resistance of telephone lines, e.g. between the subscriber and the secondary distribution frame, to be measured.