The Fluke 1577 Insulation Multimeter combines a Digital Insulation Tester with a full-featured, true-RMS digital multimeter in a single compact, handheld unit. The Fluke 1587 FC Insulation multimeter is the only meter that gives you a high-performance DMM, a state-of-the-art insulation tester and wireless connectivity through Fluke Connect® all in one unit.