Just listed a Schertler DYN-G transducer mic on ebay in case anyone is in the market. $175
Bought it right here on djangobooks a few years ago! This high-quality professional pickup sticks to the instrument with included removable adhesive putty and accurately reproduces it’s acoustic tone without the feedback issues of ordinary microphones.
Works perfectly. Has not been used much if at all in the past couple of years. Has some cosmetic scratches on top of the device. Includes box and canister of plenty of reusable adhesive putty.