Used on helicopter utility air conditioning ssystem. D18 1st end thread quantity per inch bulkhead fitting (bulkhead union no.6) DS200 bulkhead fittings mate with sae female o-ring swivel hose connections refered to as tube-o; design allows for compatability with MS28775-011 o-ring when used with r-134a refrigerant; uses AN924-80 mating nut coupling tube w/bulkhead union
