These Philips lamps feature superior color quality and very crisp white light. Incredibly high 1.95 PPF (photosynthetic photon flux) per watt per second light source. 3,100?K Green Power or 4,200?K color temperature lamps available. High 92 CRI, 33,000 initial lumens (105Lm/W). High 90% lumen maintenance at 8,000 hr/High 85% maintenance at 20,000 hr. Double glass jacketed lamp is rated for either open fixture use (without glass lens) or enclosed fixture use (with glass lens). Bi-pin lamp base is compatible with all Sun System? LEC? Brand Technology Fixtures. PLEASE NOTE: These Philips lamps are designed & optimized to be paired with a Philips brand electronic ballast. All Sun System? LEC? Brand Technology fixtures are made with a Philips brand electronic ballast(s). If these lamps are used with a different fixture type, you will likely experience a shortened lamp life and possibly premature lamp failure.