Nylon. In pantyhose, nylon has interwoven stretchy fibers that allow a form fitting, stretchy barrier around the legs. It reacts as you move and stretches when stretched. Rolland safes use nylon for the same reason. When a safe is attacked you want to make it as cumbersome as possible for any criminal. Adding nylon to the concrete lets it stretch up to 4 times farther before it breaks. Like the nylon in pantyhose, our safes are flexible and can withstand much heavier manipulation because of the concrete’s ability to move farther instead of breaking. The nylon deflects a blow and has a higher resistance.
Epic win for random factoid of the day!