Cylinder ID help please

[LilBill]

i have two sets of aftermarket 80" cylinders and need to figure out who made them and if they're worth a chit. one set has a large SF embossed on the base flange and the other set has a symbol embossed on the flange that could be a stylized letter "A" or maybe a pyramid with a diagonal line across the lower right corner. ring any bells ?
thanks