Pelican 1640 Camera Case With Foam (Black) 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. Pelican's Pick N'Pluck foam lets you customize the interior. Stainless steel reinforced padlock protectors ; Optional five-piece foam set that consists of 1 "egg crate" foam upper section, 3 Pick N' Pluck foam sections, and one 1.0 inch blank bottom foam section Interior Dimensions (inches): 23.70 x 24.00 x 13.90