Gray web sling used to carry the scope can for the MGZ and MGZ40 sight cans as well as the carrier for the 8cm Mortar sight. I'm not sure about other optic cans, but it's likely used for them as well. We have made these using our new, shuttle loomed reproduction 25mm German pattern webbing and we had the aluminum snaps hooks custom made.
They weren't cheap.
Like original Lafette Straps, originals are almost impossible to find.
Gray or olive? Your choice. Whatever rhyme or reason the Germans had for their mutliple shades of webbing is lost to history. It's NOT "Luftwaffe"- it's medium gray, not field blue, it's not SS or Brandenburg Kommando. The gray webbing was used throughout the War- on Heer and SS gear.
This gray material is seen on A-frames, clothing bags, rucksacks, MP44 and MP40 pouches- items dated from 1940-45. Sometimes it's mixed in with olive parts on the same item. It's whichever color you think looks sexier...