Pack of four high powered 30W screw fitting daylight simulation compact fluorescent CFL helix spiral energy savers with light output equivalent to a 150W incandescent light bulb.These ultra-bright ultra-white light bulbs cover the full spectrum of natural daylight making them ideal for craft work, graphic design, artwork or anyone needing a bright, high quality light. Not suitable for dimming. Features a commonly used ES-E27 Edison screw (27mm) cap/base.Need more help in choosing a suitable light bulb? Read our guide Choosing Compact Fluorescent Lamps