The Dwyer 2020 Magnehelic Differential Pressure Gauge measures pressure in inches of water, ranging from 0-20. It is a 4.5" gauge designed for HVAC and refrigeration applications. The gray-colored gauge is lightweight, weighing only 1 pound, making it easy to handle and transport. Its model number is 2020, indicating the specific design and functionality of this pressure gauge for business and industrial use.