Found this reflector "thing" on Ring Mountain (Tiburon) on the morning of 9/1. It was in the weeds right along the Shepherd Fire Road, on the north end, close to the Eucalyptus tree. Not sure what it is. Made of rubber with - two parts linked together with a red plastic link. I'll be turning it over to a Marin County Open Space Ranger to add to the lost and found. In the meantime, you can contact me here. Also, if someone could enlighten me on what it is, that would be appreciated!