You are looking at an OO Gauge Industrial Power Plant Annex and Warehouse Building, this item is printed with some assembly required like gluing together the steam chimneys and the supports in the annexe roof but is a simple job taking a few minutes before its ready to paint. I have included an overhead shot of the pieces you will receive. 

3d printed in grey PLA so easy to paint with your favourite model paints - Please note painted and finished items are not included, you will receive all grey pieces, any small character models are purely for inspiration only. 

The package includes an administrational building, connected to the power plant by a small corridor building. All roofs are removable, and the two larger buildings have separate rooms within them, allowing multiple units to occupy the buildings during a game.

The power plant has a set of loading doors that can be attached opened or closed; smokestack chimneys that can be friction fit to allow easy storage. The power plant roof have a removable ladder to allow players to use that as a manner of access to the roof. This package also has 3 separate 'bases' so each of the rooms can be placed on a printed base should you require this (shown in the pictures with the all grey items). 

Dimensions: 
Power Plant section: 13.2cm (excluding smoke stack section but 15.4cm with) x 11.5cm x 7cm (to the top of the raised windows) - smoke stacks stands 13.5cm tall
Annexe Corridor section: 6cm x 6.4cm x 4.1cm (top of pitch roof)
Warehouse Building section: 14.2cm x 10.1cm x 5cm tall

Complete footprint dimensions (quite hard to measure with pieces not being equal but i've done my best): 26.5cm wide x 19cm deep