One of the most efficient and effective light sources available to indoor gardeners, the Greenpower Lamp from Philips has a fine reputation for cultivating tremendous crops both in terms of quality and quantity! As you would expect from a premium standard full spectrum bulb, the light that is generated by this exceptional product triggers phenomenal growth in all your plants over both vegetative and flowering stages. On close inspection the advanced technology and robust design employed by a Philips Greenpower Lamp also gives you distinct benefits of increased reliability and longer lasting output at the optimum level. In other words, you have to change it far less frequently than alternative options! We recommend replacing this lamp every 6-9 months.