Please see all pics of this item here:
http://www.thefreemanfix.com/misc/
This is is a strap hanger that I made in order to use a strap on my acoustic without using a rope, electrical cord, duct tape, fishing line, carabiner clip, gorilla glue, or similar means of attaching it.
Problem: only one strap button on your acoustic.
Solution: rope, or quick-release strap hanger.
Problem: rope may be hard to untie, half of a quick-release mechanism must stay attached to the guitar at all times.
Solution: my strap hanger is easy to fully release and move to another acoustic without any extra hardware.
This is a gadget for the finicky musicians among us. I came up with the idea when I had to occasionally play my guitar standing, but usually sitting. Not wanting a strap or rope in the way, I would always untie my knot when I was done strapping. It got old fast.
This particular widget is made from a nice camouflagey belt with a boy scout style buckle. It also constitutes a genuine guitar strap button, a screw, nuts, fancy washer, and a few hours of R&D because it is the first one I built. Alpha, serial number 0001. It is fully adjustable, and when fastened, will NOT slip and drop your guitar. I suppose it could be used with most any instrument as long as there's room for it between the head and strings just in front of the nut. The belt is 1.25" / 32mm wide.
I will be posting a second similar (turquoise) strap hanger eventually, along with a video of this one being used / actuated.