Snap-on Plastic window Black ABS case Brass internal bottom connection Good quality Pressure Gauges (Manometer) for Gas RegulatorsCase sizes: 2"(50mm), "2 1/2" (63mm) Case and ring: black steel, chrome-plated steel, stainless steel Windows: glass, acrylic, polycarbonate Internal: brass, phosphor bronze, 304-casseTTs mechanism, 316 tie-in Connection:1/8, 1/4, 3/8, NPT, BSPT, BSP dependent on model ...