The Dwyer Instruments 477-3 is a versatile digital manometer that provides accurate pressure measurements for a variety of applications. 0-200" W.C. it reads positive, negative, and differential pressure. It is the ideal choice for professionals in need of a reliable and easy-to-use digital manometer. With its easy-to-read display, user-friendly interface, and durable construction, this instrument is the ideal choice for professionals who need reliable pressure readings. Whether you're working in HVAC, plumbing, or another industry that requires precise pressure measurements, the Dwyer Instruments 477-3 is the tool you can trust.