I have used the Nite-Ize PR2 bulb upgrade for large maglites (not to be confused witht the fine 3LED nite-Ize upgrade for mini-mags), and it is a poor performer in the maglite platform. It just isn't very bright. I ended up installing these in my Dorcy 4 cell dome lanterns as long running, low output emergency lights. The nite-ize replacement will fit any PR type base flashlight.

Maglite has recently released a 3 watt drop in LED bulb for their C and D cell flashlights. The 2 cell version is an amazing performer. It is bright, white, and long lasting. It puts the stock incandescent bulb to shame. I have not tried the 3 or 4 cell versions, but plan on upgrading my 3 cell maglites as soon as I can find the 3 cell bulbs. These replacement bulbs have a unique base and are designed exclusively as a maglite replacement.

Good luck, TR