You buy the flow meter from dwyer; they have a website but i can't remember the exact url. Henry, as far as a regulator goes, try a beverage supply place; anything that will fit on a CO2 bottle, and lower the pressure to 15-30lbs pressure. You need 2 guages, one for tank pressure and one for working pressure. Welding supply houses might have them too, but make sure they'll fit CO2 bottles. I think the fitting may be different for flammable gases. (Not sure)

The beauty of this flow meter is that you don't need to buy a fancy aquarium regulator with a needle valve; the flow meter replaces the needle valve and works way better.