From Bombardiers’ Information File, U.S. War Department, March 1945:
Vest Type Emergency Kit
The following items of equipment are carried in the packets of the vest: 1 hat (yellow on one side, OD on the other)1 pair polaroid sun goggles1 signal mirror, with lanyard1 sharpening stone1 fishing-sewing kit, in plastic container1 collapsible spit and gaff1 plastic water canteen (3-pint capacity)1 Boy Scout knife1 large knife (with 5-inch saw and blade)1 package toilet tissue10 yds bandage (with sulfa powder)1 waterproof match-box with compass20 matches14 fire starting tabs1 burning glass1 signal whistle1 oil container1 waterproof cover for .45 cal. pistol20 .45 cal. shot cartridges1 First Aid Kit1 Survival manual2 vest-kit rations in tin containers2 five-minute signal flares1 mosquito headnet1 collapsible container for boiling water1 pair woolen insert gloves1 pair leather outer glovesVest, Emergency Sustenance, Type C-1 was developed for the use of each crew member of an airplane forced down in isolated regions. It consists of an adjustable vest-like garment, fitted with pockets into which the items of the kit are conveniently stowed. The vest is to be worn under the life preserver vest and parachute. PROTECT YOURSELF: Before taking off on a flight over inaccessible or mountainous country, the Arctic, jungle, desert, or ocean, check your vest and be sure it contains all the necessary equipment. If it does not, check with your Personal Equipment Officer.
I had one of these vests in my collection for a while. Traded it for some old maps.