Liquid glycerin filled 0-30 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