[derk derin]

Hi All,
Well I seem to have found another mystery item that needs identifying. I have a pair of white webbing straps, manufactured by Woods and dated 1939 so early wartime produced. The bottom strap has stencilled numbers & letters on them. Maybe this could help identify what they were for? The blacked out square looks like it used to be 51.
I put them next to the medical corps stretcher carrier shoulder straps and they’re too short for that purpose.
Any ideas?
Thanks,Derk