The Fluke 1587 and 1577 Insulation Multimeters combine a digital insulation tester with a full-featured, true RMS digital multimeter in a single, compact, handheld unit, which provides maximum versatility for both troubleshooting and preventative maintenance. Whether you work on motors, generators, cables, or switch gear, the Fluke 1587/1577 Insulation Multimeters are ideally suited to help you with your tasks and at a cost that is far less than buying the two products.