This heavy-duty steel dropbox from is perfect for protecting small valuables, such as mail and important letters, rent checks/payments, keys, etc. The dropbox can be set in an office or home doors, or walls, up to 1.75 thick, with easy-to-follow manual instructions for installation. The mail slot on the front of the dropbox cannot be pried open for theft, and this dropbox can only be opened from the back with a key.