Milton 1/4" NPT Pressure Dial Gage. this pressure gauge for reliable service with compressors, regulators, air lines, pneumatic tools and equipment. Made up of a brass mechanism, ABS case and a polycarbonate lens, this gauge is resistant to heat, corrosion, water, salt water and oil. The 1/4" NPT pressure gauge has a bottom mount and offers a pressure range of 0 to 300 PSI. 2" face diameter.