Compatible with 13, 18, 26, 32, and 42 W electronic programmed start ballasts, PL V 11W DIR and PL V 11W DIR HIGH CRI Lamps require no rewiring during installation. Units also feature ballast smart control technology which allows performance on lower powered ballasts. PL V 11W BYP Lamp requires bypassing ballast during installation and runs directly off line voltage. All turn on instantly, last 40,000 hr, and feature round diffuser that optimizes overall light output.