When you select Philips TuffGuard™ Fluorescent lamp with ALTO® lamp technology, you are reducing the impact on the environment, while the coating helps to protect your customers, employees and reputation. Philips TuffGuard™ fluorescent lamps meet sustainability requirements because they reduce the impact on the environment with low mercury, energy efficiency and long life. The patented green endcaps mean you're using ALTO low-mercury technology. The 16 mils thick coating on TuffGuard™ fluorescent lamps forms a protective seal from end to end and is guaranteed to last the average rated life of the lamp under specific conditions.