What is this pocket for??? Its on the back of the right shoulder of this Penfield jacket I bought at a flea market. It's a “full size” pocket (same size as front

What is this pocket for??? Its on the back of the right shoulder of this Penfield jacket I bought at a flea market. It's a “full size” pocket (same size as front

What is this pocket for??? Its on the back of the right shoulder of this Penfield jacket I bought at a flea market. It's a “full size” pocket (same size as front

What is this pocket for??? Its on the back of the right shoulder of this Penfield jacket I bought at a flea market. It's a “full size” pocket (same size as front