The Extech 380320 analog insulation tester features a large easy-to-read analog display. Providing three test voltages (250V, 500V and 1000V) and insulation resistance to 400MΩ, the Extech 380320 analog insulation tester also has a "Lock Power On" feature to be used for extended test times.

The Extech 380320 analog insulation tester measures continuity to 3Ω, resistance to 500Ω, AC voltage to 600V, and a 1.3mA short circuit current.