Most gas cylinders are high pressure vessels. Pressures range from 100 psi (or lower) to 6000 psi and up from there. The gas in the tank requires a pressure regulator to reduce the pressure to a usable point.
Single Stage and Dual Stage regulators are commonly in use in a variety of applications but few people recognize the difference in the two.
So, if your application is pressure sensitive and you need a particular pressure held true for a period of time a dual stage regulator is your best choice.
If you are using high purity or ultra high purity gases be sure to utilize a pressure regulator that is constructed of materials compatible with those grades of gases. There are vast differences in the quality of regulators available. A very good regulator for high purity or ultra high purity gases will have a machined brass body with stainless steel diaphragms, Teflon and Tefzel seats and seals and a Helium leak integrity of 1 x 10 to the minus 9. These regulators are also available in stainless steel but the necessity is usually reserved for Electronic Grade gases and corrosive gases.
Using an Industrial Grade regulator on a high purity or ultra high purity gas will result in putting back the same contaminants we remove from the gases to make the high purity or ultra high purity in the first place.
Regulator recommendations are always available from Middlesex Gases & Technologies.