The Miscellaneous Product Accessories A258B Time mark Phase monitor 480V 10A is a cutting-edge monitoring tool made to guarantee that HVAC systems operate at peak efficiency and safety. To identify any problems like phase loss or imbalance, this novel device continuously assesses the phase quality of electrical currents in 480-volt systems. https://www.partshnc.com/a258b-miscellaneous-product-timemark-phasemonitor-480v-10a