Ship flat and easy to fold together. Pre-scored and glued, corrugated. Inside space is 2-3/4" x 1-3/4" (x 2" tall). Top flap is approx 3" wide.
See the Treasure Chest Trims Collage Sheet for some options to turn these into a pirate's chest. And a couple of pieces from the Small Chipboard Hinge & Straps Set are shown in the photo below for size.
These are also included in the Beneath the Sea Kit; see all the other kit components available to buy separately.
Set of 2.