The Dwyer 0-40 Inches W.C. Gauge Minihelic II Gage is a precision measuring tool used in the HVAC and refrigeration industry. This digital gauge allows users to accurately measure vacuum or pressure levels up to 40 inches of water column. The Dwyer brand is known for its reliability and quality in producing high-performance instruments for various industrial and commercial applications, making this gauge a valuable asset for professionals in the field.