Pressure seal
From Halopedia, the Halo wiki
Template:FOF-1 Pressure Seals are components of the MJOLNIR Armor system developed by the UNSC and used by the Spartans. They are probably located throughout the armor system and used in joints and where armor pieces come together. They serve to keep the Hydrostatic Gel from leaking and keep the atmosphere inside the armor, keeping it airtight underwater or in space. They break when put under extreme pressure, such as in a high velocity impact or when the Hydrosatic Gel has been overpressurized.
