All of the following items can be ordered from mcmaster.com or propane products
7976A34 12' Hose With 9/16"-18 Lh (B-Size) Fittings $19.25
7920A4 Welding Hose Coupler 9/16"-18 (B-Size), Lh To Lh Threads, For Fuel Gas $0.91
7976A21 Propane Torch Adapter Bulk Tank-To-Hose Connector w/pol Valve $6.60
PART-350WPHOSE 350# 1/4" ID High Pressure LPG Hose (10' length) $24.95
HANSEN-QCC Hansen Gas Mate Quick Connect Fittings 1/4 Plug & Socket $24.95
The air hose from propane products has a Pol connector on one end and a 1/4 npt fitting on the other. This will connect direectly to the Hansed Gas Mate Quick Connect Socket. The result is a high pressure propane hose with a Pol (tank) connector on one end and a quick connect socket on the other.
The Hanson Gas Mate Plug can then be attached to the FKO device. An advantage of the Hansen Quick Connects is that they have a check valve on both sides which will prevent a WallySituation. The other advantage is they are rated for propane. Cheap air hose connectors are not rated from propane and have a definite tendancy to leak.
Important! The reason to be wary of cheap air hoses is that they are often made out of a synthetic rubber called EDPM. Experience has shown that propane causes such air hoses to burst. I've seen an air hose that has been used once for propane service, rupture later when used in air service.