... steel case Brass internal Bottom or back connection Good quality Liquid Filled Gauge w/Bayonet ... polycarbonate window,brass or stainless steel internal and connection. Specifications are as follows:1) Dial size: ... 2", 2.5", 3", 3.5", 4", 6"2) Connection size: 1/8", 1/4", 1/2", 3 ... and bayonet ring: stainless steel5) Material of the connection and internal: brass, chrome plated brass, stainlesssteel6) ...