Stainless steel double stage,
9400 series, super rare.
3800 series, appear from time to time.
3870 series, miniature, rare
3??? Seris, old, similar to Parker Hannifin DSG 750 series, can't pull out the model number right now.
Brass double stage,
Model 8, really old, Harris standard 1/2-27 stem to body connection threads, no recommend
3120 series, same as 3800 but in brass
3104 series, heavy duty, really big and heavy.
And there are some other models available.
There is a matheson reg in S/S section right now, advertised as double stage but actually is a matheson B15 heavy duty single stage reg.
Matheson is under Harris group, some other Harris regulators are OK, work well for our system.
Last edited by Bettatail; 12-30-2012 at 04:54 AM.