This set features three variants of the massive bunker entrances, which are part of the stretchgoals of the Full Spectrum Dominance campaign. 

Each large concrete construction is wide enough to fit a tank inside, and is equipped with a top slot for different kind of turrets. 

The models are provided as .stl files and are PRE-SUPPORTED. They have been extensively tested at 6mm scale.
The models can be easily upscaled to 10mm (150%) and to 15mm (240%, but we recommend re-supporting).