When there is no way to attach the shade to the lamp, the bulb clip clips directly on to the bulb. The clip may be built into certain shades, or you can purchase one of these, which attach to our standard shades. This Edison (round) clip is used for standard Edison bulbs, and we also offer Candelabra (flame) bulb clips, which attach to chandelier bulbs. This product comes in a one-size-fits-all standard size.