Type unknown to us and possibly experimental as we have not been able to find another example. 2 3/8” greatest dimension, made of two heavy gauge steel equilateral triangles slotted together with each of the four inner angles gas welded. We have a small group which recently came to market in southern Germany. All have cleaned pitting mixed with original surface. It seems likely that, as with some other German militaria, these were deemed ineffective or too labor intense with very limited use.