The Ransome Venturi is a terrific high pressure gas mixer. It will work great for propane (0-25 psi) or natural gas (like 2-5 psi). This venturi mates with the #250 head as well as all the larger heads. It can function just as well with the smaller heads as they all have the same 1-1/2" threads on the back end of the burner head, but the smaller heads will go with a less large Venturi like the V125 or the V100 as a better size match. Great price! and a great product. $235.00