Machine woven variant of SS collar tabs. These were simply made using a different style of manufacture than the embroidered pattern tabs. These appeared relatively early in the War (1941ish) and were worn on all models of Feldblusen regardless of fabric. (There are some fairy tales floating around they these are only for HBT/ cotton uniforms...that's total nonsense.)
These come flat and unfolded. The simplest way to deal with them is to cut muslin or cardstock backings, wrap the edges around and lightly glue (or press on low heat) then sew on like the ones in the photo.