This is my best antique store find to date. A CD 123, EC&MCo, S.F. in aqua or blue(?). It is a B-mold: squared dome, straight skirt, button on reverse, small top loop ampersand. There is a whack on the back, with a much better than average base. Lucky happenstance finding this one. The antique store was next door to my Nevada lunch stop. I spotted it on my second pass through the store after the antique dealer said I saw all of the insulators already. Ha!