The 8506A Digital Multimeter uses a fast thermal rms sensing technique for measuring ac which very significantly advances the state-of-the-art for ac measurements using a system DMM. It is several times more accurate than the calculating type of true-rms converter and is unmatched by any other DMM. Basic ac accuracy uncertainty is reduced to 120 parts per million, 24 hours for frequencies from 40Hz to 20kHz. Features • 6 1/2-digits • DC voltage to 1000 V • AC voltage to 500 Vrms