Work with the best. The Fluke 323 True-rms Clamp Meter is a great clamp meter for general, grab-and-go troubleshooting needs. Fluke rugged. Fluke reliable. Fluke precise. True-rms measurements and optimized ergonomics make the 320 Series Clamp Meters the best general troubleshooting tools for commercial and residential electricians. The Fluke 323 model is ideally suited for current measurements up to 400 A in tight cable compartments.