Review on Enhanced Precision and Control with Western Enterprises VN 500 Flowmeter Regulator by Doug Virden

You won't find a more convenient regulator/flow meter than this. I bought the VN-500 because newer azeotropes like R-410A are becoming more common. With the VN-500, you can quickly and easily go from purging, supplying the right amount of nitrogen to braze, and then quickly pressurize your job to any pressure up to 500psi. This regulator is suitable for HVAC professionals or anyone who needs to use nitrogen for brazing or leak testing. No tools are required to attach any size nitrogen tank to a J-valve; simply tighten by hand. It costs money.