A small bunker from which a soldier fired a mounted machine gun. It was used to prevent Soviet infantry advances. It's shell-like design gave the operators shelter from fragments thrown by the explosions of Soviet tank-shells and grenades. The pillboxes could also come in a camouflaged variation.
It is perfect for taking out infantry, but not very effective against heavy vehicles, meaning Soviet tanks could easily overwhelm Pill Boxes. Aircraft and long range weapons could also quickly destroy it with impunity. However, formations of Pillboxes used in conjunction with turrets and vehicles is a formidable and cost effective solution.