WW2 Gravity Knife (s) Marking ? RBNR

[tony75]

Hello

I have a gravity knife here that is rbnr marked with a property stamp (s).
Doing some research, some indicated that (s) is a army marking?
Thank you for your time and help
Tony

[lucabrnroma]

Hi... S (like also 5 and 6) are found on the spike of SMF flieger knives and also on kombat knives..it should be a Luft acceptance mark...not sure if other branches used it :9

[rbminis]

The manufacturer "S" and "W" also found on Luft. fighting/boot knives is unknown at this time.
Ralph.