Our Easy-To-Read Pressure Gauge With Dual Scale (PSI & Bar) Helps You Monitor The Pressure Inside Swimming Pool, Aquarium, Hot Tubs, Spas And Other Water Systems. The Written Indicators On The Bezel Eliminate Guesswork, Making Our Gauge Ideal For Anyone Whos New To Filter And Water System Maintenance. This Pool Filter Pressure Gauge Can Be Used To Measure Water Pressure, Air Pressure, Hydraulic Pressure, Oil Pressure, And Any Non-Corrosive Medium. Dial size: 0-60 psi Accuracy: ASME B40.1 Grade B Accuracy Compliance ± 3-2-3 % of span. Thread Type: 1/4' NPT Dual scale: Psi / Bar