DuraBox Through-The-Door Locking Drop Box (D500) Durable steel construction provides secure all-day depositing of valuable or private items such as cash, checks, car keys, remotes, small envelopes, and more. Designed to be mounted on and through a door requiring a rectangular cutout for the unit. Deposit slot opening is 9-1/2" wide and accomodates items up to 1-3/4" thick. Lock type: tubular key, Capacity: 505 cubic inches, Exterior dimensions: 15" H x 12" W x 6" D, Weight: 17 lbs Because of the security baffles, this unit is not ideal for receiving large mail items such as books, magazines, catalogs, booklets, manila envelopes, and other larger mail.