Extech MG325 CAT IV Insulation Tester 200 Gohm and TRMS Multimeter 1000V measures insulation resistance up to 200GΩ and measures AC/DC voltage up to 600V. The Extech MG325 features polarization index and dielectric absorption ratio measurements, low resistance measurements, adjustable test duration timer, pass/fail comparison mode, manual datalogging up to 99 points, and much more.