Osram Dulux D 18W 840 Specifications : The Osram Dulux D can be used in combination with a conventional ballast. The lamp has a short and compact lamp base type G24q-1. This means that each of these compact fluorescent lamps has a base with 4 pins. The lamps Osram Dulux D/E 13W 840 has a length of 131 mm. Osram Dulux D 18W 840 has an energy rating label of B and an average lifespan of 20,000 hours. If the lamp starts flashing and has a delayed start-up time then it needs replacing. Osram Dulux D 18W 840 Uses : The Osram Dulux D/E 13W 840 can be used in many different places. The 4000K produces a sharp white light that is referred to as 'cool white'. This is ideal for working environments and so is most commonly found in warehouses. Note: If you are currently using a fluorescent lamp, you cannot select a different wattage from which you are now using. This is because different wattages require different gear and have different lengths.