There are also medium sized candelabra sockets, sometimes referred to simply as candelabra. I have several lamps. So very carefully I order these minimal candelabra on a standard base and they fit perfectly. And now, instead of the special Philips T4 bulbs, which cost $8 per bulb, I can just use a standard 84-cent bulb, and I've even been able to use a new LED bulb, which is much cooler and lasts 22 years. The light output is the same as the old Philips 100W, but lasts significantly longer. E26