This is a small ladder shelf. It came in 9 labeled pieces, with a bunch of little hardware pieces (no extras included).  I didn’t find it unusually difficult to put together, although the instructions are a bit mislabeled. It suggests two people, but I managed by myself with two phillips head screwdrivers. 

The width of the whole ladder unit is 15” and very bottom of the legs are 14” deep.  There’s 5” of space underneath of it.
 The interior dimension of each shelf is 12” wide and each shelf is 2” deep.  Shelves are approximately 12” apart from each other.  I measured the front-to-back interior dimensions of my shelves to be 4”, 6.75”, 9.75”, and 12.75”.  I chose to caulk the interior edges of the shelves to keep water from entering the cracks. 

The total ladder height is 53.5”, but the top shelf is only about 43” off the ground so it appears smaller.  It works out well because I plan to use it for my kids’ bathroom and they can reach all the shelves,