[Sheepdip]

I made my own about 15 years ago. All the cookie cutter ones I looked at were poorly made and not very secure. And they wanted way too much $$$

Mines made from 12ga welded construction painted mild steel, the side access door was 1/4" steel with a 1" keyed deadbolt sourced thru Mc Master Carr, it has a false bottom that sits 6" up over the "J" bolts that poured into a concrete pad/base, when the door opens it has an internal flap (an internal extension of the door) that lifts up for 2 purpose's .....to help lower the mail gently to the bottom which is about 30" down, plus it blocks sticking anything in there from above to try and snag my mail.