Model 350 3‑phase voltage monitor is perfect for heavy‑duty applications such as rural pump panels, commercial and rural HVAC equipment, and oil rigs. The Model 350 is a versatile voltage monitor designed for 200, 400, or 600V applications. The Model 350‑200 monitors 190 to 240V input voltages, the Model 350‑400 monitors 380 to 480V input voltages, and the Model 350‑600 monitors 475 to 600V input voltages.