I have a Dual 10" truck box. It is perfectly sealed. About .6 cubic ft per chamber. Custom fit for a Ford Ranger Regular cab. Has 1/2 inch plywood faces to save depth(these trucks are tiny) and 3/4 inch particle board everythign else. No splits in the particle board, 2 tubes of liquid nails were used, and a million pre drilled, liquid nails filled screw holes then put the screws in for super strength, countersunk screws in it. Also has polyfill as you can see.