For the suit’s creator, the International Latex Corporation in Dover, Delaware, the toughest challenge was to contain the pressure necessary to support life (about 3.75 pounds per square inch of pure oxygen), while maintaining enough flexibility to afford freedom of motion. A division of the company that manufactured Playtex bras and girdles, ILC had engineers who understood a thing or two about rubber garments. They invented a bellowslike joint called a convolute out of neoprene reinforced with nylon tricot that allowed an astronaut to bend at the shoulders, elbows, knees, hips and ankles with relatively little effort. Steel aircraft cables were used throughout the suit to absorb tension forces and help maintain its shape under pressure.
— Read on www.smithsonianmag.com/history/neil-armstrongs-spacesuit-was-made-by-a-bra-manufacturer-3652414/