These cups used to be regular 8 oz. styrofoam cups. Then I put them on Argus during a 16 hour dive to 700 meters deep in the ocean. The pressure pushing down on them pushes all the air out and yielded them this size when they came up!
For every 10 meters below the ocean’s surface, 1 atmosphere (atm), gets added in pressure. 1 atm = 14.7 pounds per square inch. So, at 700 meters, these cups had about 1,022 pounds per square inch of pressure on top of them!