Unit markings on belt, need help. Thank you!

[STUG III]

Just bought this HEER aluminum buckle with tab and belt. Belt is MM and dated 1940. I include a photo, I am unable to make the proper punctuation on top of the letter U with my computer. Any ideas on the unit? Looks like 6. 40 FU. Thank you. Dave.

[Gran Sasso]

Thats not a unit, this belt was given out by the storage center located at Fürth (FÜ) near Nürnberg.
Usually items from there where meant for the RAD.