A screw in bulb that gives you an eerie short circuit effect! Blinks on and off sporadically, then stops for 5 or so seconds, then comes back on and blinks again in rotation. It can be turned on or off with a toggle switch on the bulb. LED projection bulb fills the room. The plastic white bulb has a standard E26 size screw in, fits a normal light socket. Includes (1) bulb. Detailed instruction sheet included. For indoor use only. ETL listed. Measurement: L 3 in, W 3 in, H 5.5 in.