Automatic Pressure Purge System: Seahorse's Automatic Pressure Purge System guarantees a perfect seal by incorporating its own O-Ring under one of the latches. You will never forget to set the valve since it automatically activates when closing the case. Pressure is released as you open the latch. Molded-In Padlock Hole: Each case has one molded-in padlock hole to secure your valuables. The padlock holes will accept "TSA" and most standard padlocks. Accuform Foam: Optional multilayer protective pre-scored cubed foam. Accuform Foam in Seahorse cases consists of a layer of egg crate foam in the lid, a thick cubed foam center, and a 1/2" thick high-density shock-absorbing foam bottom layer. Waterproof Panel Kit: The Seahorse Panel Kits are used when specific equipment needs to be kept protected even when the case is open. These two plates are made of .063" brushed aluminum and include screws, one perimeter gasket, and O-Rings for the screws to waterproof the bottom portion of your case.