E27 15w 20w 23w energy saving bulb tornado performance in spiral shape philipshighly efficient energy saving bulb now with 50 longer lifespan 12 000 hours particularly high light yield through curved bulb form a very big advantage of this energy saving bulb is that the external diameter of the curved bulb shape also called a spiral is greater than that of the socket through this the light is also dispersed backwardsdownwards towards the base this is very advantageous with even