This bulb really belongs in the vintage gallery, but I put it here so it could be together with the 3 loop fil. Recycled bulb. At some point in time, this bulb was a non-working Mazda bulb with a tungsten cage filament. Apparently, it was a 40w 115v bulb (some of the stamping on top is still there). In fact, this bulb used to be a tipless bulb! Hence the existence of an evacuation port on the stem. It was picked up by a bulb recycling company in the 20's (possibly SYLVANIA, a company that started out recycling bulbs), which then made a big hole on top, snapped off the glass rod and pulled out all of the contents, fitted in a new carbon filament and then finished the job by evacuating the air from the hole on top. Such companies could only fit in new carbon filaments because they require no supports (contrary to the brittle, long uncoiled tungsten filaments which need many supports). Amazingly, this bulb makes the phrase "All tipped bulbs were made before 1922" to be false! It can also be a confusing item since many recycled bulbs are etched with "Mazda", and all Mazda bulbs had tungsten filaments. There is a small glass stub at the top of the stem, which is all that is left of the glass rod that once held a cage filament in place. It seems that these recycled bulbs were quite popular, as they are not that hard to find on eBay. The tip of this bulb is larger than normal, because the hole made on top needed to be large enough to fit in the tools to attach the new filament in place using carbon paste.