[Milsurplus] SJO cable used in extension cords, for HS-33 type headphones with 1/4" bailout jack.

[John Hutchins]

All I have "restored" some head phones,  The 6' extension cords 
conductors insulation was shot.  These were post WWII types with plastic 
insulation, just cracked and kept cracking
I  had taken the time to soak the cords in DOT 3 and the rubber jacket  
became soft.
So what were the old specs for these cords 18/2 SO ?

Source of so.sjo cord  2/3 conductors ?
Have HomeDopot in mind, not the best solution.

Thanks