Philips 539980 2nd generation of T12 plug and play replacement lamps are now T8 size - The 6500K color is obsolete and is now only offered in 5000K - This lamp replaces the discontinued 20T12/EM LED/48 6500K This lamp fits into your existing fixture and replaces a 48 inch fluorescent tube. 1800 lumens, 82 CRI 36,000 hour rated operates on approved magnetic T12 ballast NOTE: Do not use on T8 electonic ballast or T12 electronic ballast. This tube will only work on T12 balllast. This is a glass tube shrouded lamp, these lamps are a great plug and play replacement. No rewiring or extra work. Simply remove your T12 1.5 Iinch diameter) fluorescent lamp and plug in your new Philips Instantfit LED T8 lamp!