Help with unknown patch

[josephc]

I received this patch along with the NSKK patch and SA service pin I posted in other threads. These all come from estate of US 8th division medic.
Patch is tan and round and dated 1933 or 1938 on back. Looks like a rank symbol on front. there are some numbers or letter S with line on back that I can not make out. Can someone tell me what this patch may be?

[John4022]

I want to say its a Wehrmacht rank pip for a summer drill hbt uniform.

[bigmacglenn]

Oberschuetze...equal to a Private First Class in the US Army...
cheers, Glenn