Pelican cases are kept watertight through the use of a tongue and groove fit and a polymer o-ring. Pelican cases come standard with an Automatic Pressure Equalization Valve which releases built up air pressure while keeping water out. 3-Piece Foam Set Stainless steel reinforced padlock protectors Interior Dimensions (inches): 35.75 x 13.50 x 5.25 Watertight, Crushproof & Dust Proof Open Cell Core With Solid Wall Design Easy Open Double Throw Latches O-Ring Seal Automatic Pressure Equalization Valve