This is the OMS Stage SPG Pressure Gauge 550 PSI with Swivel Features: High Contrast Face designed for easy viewing in low light situations Brass Housing Nickel finish The OMS Stage Gauge is lightweight and compact, perfect for stage and deco bottles or lightweight travelling reg sets. OMS submersible pressure gauges (SPG) come with the necessary O" ring swivel for installation. These gauges are light, small and perfect for stage bottles or people that are just looking for a smaller gauge."