Nite Ize 1.5-Volt LED Flashlight Bulb in the Flashlight Bulbs department at Lowes.com
Lumencraft LED Conversion Kit Compatible/Replacement for Maglite Flashlights, 325 Lumen, High Power SST40 + Scratch Resistant Glass Lens. Fits 2-6 D and C Cell Focusable (325 Lumen + Glass Lens) - - Amazon.com