Philips T12 fluorescent lamps provide high performance in a wide range of sizes, shapes, and types. F20T12/D ALTO 30PK. 20 watt - 24 - T12 -Medium Bi-Pin - (G13) Base- 6,500K - Initial Lumens: 960 -Design Lumens: 960 - CRI:73 - Reduced mercury content - Daylight ALTO Fluorescent Philips Light Bulb.