Uniweld R1549 NITROGEN REGULATOR (5-175 PSIG)- Nitrogen Gas - Protective rubber gauge boots. - Adjustable pressure screw with locking nut. - Porous metal inlet filter on Nitrogen and air regulators, but not installed on CO2 models. - CO2 models with 1/4" SAE flare outlet have a built-in reverse flow check valve. - For all of your testing and evaluating needs. Dimension Depth: 3” Width: 5-1/4” Height: 5-1/4” Weight: 2 lbs.