Maglite LED Conversion and Upgrade kits: The best and cheapest dropins and replacements..
LED 5W Cree 390 Lumen Bulb for MAGLITE® 3-Cell Flashlight 3.6V 4.5V – Draco Products
Nite Ize LED Flashlight Bulb in the Flashlight Bulbs department at Lowes.com
HQRP Ultra Bright 300Lm High Power 3W LED Conversion Upgrade Bulb for Maglite 2D 3D / 2C 3C / 2-3 D C Cell Flashlight Torch - Walmart.com
JOMITOP Led Conversion Kit, LED Bulb Replacement for Maglite Flashlight DC 3W 4.5V 6V 9V 12V Upgrade Bulb on 3 4 5 6 Cell Lantern Flashlight Torch 2 Pack P13.5S - - Amazon.com
2x HQRP 3W 3.2V-9V DC LED Bulb for Maglite 3D 4D 5D 6D 3C 4C 5C 6C Flashlight | eBay
Flashlight LED Conversion Kit Bulbs 3-6 Cell C&D for StreamLight or MagLite Torch 🔦⚡ - YouTube
MagLite 3D LED Upgrade - 1400 lumen CREE XM-L U3 bulb - YouTube
HQRP Ultra Bright 300Lm High Power 3W LED Conversion Upgrade Bulb for Mag-Lite 3-4-
Lumencraft LED Conversion Kit Compatible/Replacement for Maglite Flashlight - 2000 Lumen for 3 D Cell - High Power Upgrade for Maglight with 12x Cree XTE Emitters - - Amazon.com