Ran across this little device in my collection of pics. I had forgotten I purchased it along time ago. It’s called a Buznut string dampener. Searched the forum to see if anyone had ever used one before and found no entries.
It’s an evolution of a string dampening device originally created by George Van Epps. Some notable guitarist in the 60s who played arch tops such as Herb Ellis and Scotty Moore used the original headstock mounted contraption to dampen strings that were causing ringing and feedback. I mounted this again to check out its properties. It does dampen open strings, and can be adjusted to allow the strings to ring in between the little felt pads by pulling or pushing on the device. It does quiet the guitar down quite a bit and I can see it being useful especially in amplification settings where volume and feedback can be an issue. May give it a try at Friday’s gig.