im missing a part on my co2 regulator?

picture 1 im pointing to the part i need, the other side hooks up to tank.

picture 2 im pointing to what i think is where my tubing goes,is this correct? also there is an adjustment valve on the front thats goes from .5-2.0 is 1.5 the same as 1500?

I am pretty sure what you have is a two stage regulator that big round gauage tells you your bottles pressure (inlet) and the clear guage with the little ball in it (flow meter) tells you your outlet pressure (working pressure). normally on those types of regulators the outlet line would connect at the bottom or the bottom-side of the flow meter. with that big guage you should be able to adjust the amount of pressure coming out of your bottle by turning that nut that is just below the guage on the regulator body. the big guage should be in 1000's (psi) the flowmeter is also in psi but not in thousands it is usually exactly what is says, so if the flometer is reading 10 or 20 then it is 10 or 20 psi. the flow meter also has it owwn knob you turn to adjust your flow (working pressure). You might even have it hooked up wrong you have the flowmeter hooked up to the bottom of the regulator it should be coming off the side, where you are pointing in pic 1, you will have to get to a weld shop and get a cap for the bottom of the regulator. Pic 2 after looking alittle closer it does look like that is where you put your hose connection, on the bottom of the regulator it there looks to be a little black knob and if i am not mistaken that would be your actual flow flow meter to adjust your working pressure. if i need to clarify anything just ask.