Zenport LPG400 Zen-Tek Glycerin Liquid Filled Pressure Gauge, 400 PSI Liquid glycerin filled 0-400 psi pressure gauge; grade A accuracy of 1.6% full range 2.5-inch (63.5mm) diameter ABS case with 372 plastic window; 1/4-inch NPT bottom connection; brass internals and connection Dampening action of the liquid makes readings possible during conditions of rapid dynamic loading and vibration Better performance in corrosive environments and immunity to moisture penetration and icing Liquid helps to lubricate all moving elements, improving the lifespan of the gauge; high visibility dial face and numbers