The Dwyer 308 is a Series 300 Durablock Solid Plastic Stationary Gage in a vertical style for highly accurate laboratory or general industrial service. It measures low range gas and air pressures, positive, negative or differential. To assure the accuracy required in instruments of this type, all machining of bores and wells is to the highest standards of precision backed by Dwyer’s years of experience in the fabrications of acrylic instruments.