I bought a couple Mag-Lite AA combo 3 white light LED conversion kits from Nite-Ize. It appears the threads are not the correct pitch on the screw on end caps. I couldn't get either switch to screw into the Mag-Lite bodies properly, but the LED bulbs work fine. Not very bright, but I don't anticipate changing blown bulbs as often as I once did. Should get much longer battery life now also? The combo kit usually sells for a buck more than just the bulb with reflector. Even with the screw on end cap, you still have to turn the bezel to activate the light. If I were to buy again, would only buy the bulb kit. Paul.