Philips MasterColor CDM Lamp 315 Watt Argo P 3100K Superior color quality. Crisp white light. Very High 1.95 PPF per second light source. 3100k color temperature High 92cri 33000 initial lumens (105Lm/W). High 90% lumen maintenance at 8000 hr / High 85% PPF maintenance at 20000 hr. Unique Open Rated Lamp construction reduces radiant heat from the arc tube and is suitable for open fixture use.