Obviously professionally made with serious intentions. The only clue to it's origins is the letters S.S.A.71 stenciled on the inside of the chest panel.

Strap at each sleeve-end is 110cc (42 inch) long, riveted and sewn in with a buckle (see close-up right). Original intention of these two buckles/straps is not obvious. Various configurations are possible - and the jacket can be made secure in more than one way if imaginatively applied.

High collar is made from soft fleece-like fabric.
Webbing side arm loops prevent arms sliding up or downwards.
Workman-like webbing straps (all 35mm wide) are all riveted and sewn . Robust metal buckles are quite simple thread-through type with
efficient slide-claw mechanism.