Original glass mine pressure plate.Price is for one randomly selected plate.Made from thick dark brown glass with 2 grooves used for twigs to adjust the pressure required to activate the mine. Some have minor chips, see photos.The glass mine was one of the worst mines you could encounter as it contained a nominal amount of metal which made it almost impossible for mine detectors of the era to find. If you were unfortunate enough to activate one, the resulting shrapnel was not only devastating, but also nearly impossible to remove as the shards are visually difficult to find in a wound, stay sharp for eternity, and being glass, they can not be fished out with magnets. Highly effective, cheap, and perfectly horrid - although I am sure many of the worst elements of this were not intentional, just by products of making them from a cheap and readily available material.