Here are a pair of glass cups I found while scratching around an old dump. The dump area I was digging was producing just about all electrical stuff. The one on the left is 2-1/4" in diameter x 1-5/8" tall....the right one is 2-1/8" in diameter x 2-3/8" tall. Both have "AC" boldly embossed on the bottom, which is correct looking into the cup, backwards looking from the bottom. No other markings. The glass is fairly thick with a few small bubbles. They also have three tabs molded into them, the short one has them on the bottom and the tall one around the rim flange. Any ideas? Answer: these are automobile fuel filter or fuel pump bowls from back in the day. AC (the spark plug company) was the manufacturer. Many thanks to Douglas Moody and Bill Kemp for their responses.