I just got this and it came out of a thrift shop in Massachusetts. This is an 1825 B&R (Brown & Robinson) LRI Insulator which is the oldest glass insulator in the world. In two years it will be 200 years old! Unbelievable! Bob Berry wrote an article on this insulator a while back. I believe this is one of two known. I spoke with a person who is related to the family that made this at the New England Glass Company 1818 -1888. By 1849 NEGC was recognized as the largest glass company in the world. NEGC made a lot of what we call Flint Glass which is basically glass with lead in it. It weighs about 2 pounds. It went up the side of a house or barn and was either mounted in/on a wood plank or grouted into a masonry chimney in lieu of a brick. It makes my 1840's bureau knobs look modern! LOL!!!!