When a pilot ejects from an aircraft, he is equipped with a survival kit of useful things that will hopefully allow him to look after himself until he can be rescued or make his way back to friendly forces. This pilot would be wearing his flight helmet at the time he ejected, but once on the ground this is quickly discarded as being heavy, bulky and unnecessary. Removing the helmet creates its own problems, however. The head is an area where it is very easy to lose body heat and in cold conditions, keeping the head warm and dry is essential. To get around this problem, survival kits come with an emergency hood for the downed airman to wear. It is made of olive-green waterproof nylon that is both camouflaged and waterproof: 

The hood has a large neck curtain around its base, and this can be tucked into clothing to keep wind out and help maintain body temperature: 

Again, to help maintain the shape of the hood and keep it tight to the body to retain heat, a pair of drawcords are provided at the face opening and the neck: 

The inside of the hood is lined with a warm cotton fabric to help keep the wearer warm: 

The label inside dates this hood to 2015 and shows it was made by Beaufort, the leading manufacturer of aircraft and sea survival equipment in the UK: