<p>★★INSTALLATION INSTRUCTIONS★★<br>1. Start by unscrewing and completely removing the head of your Maglite flashlight. (if the head is not completely removed from the body you may have issues with the dropin sitting down in the head correctly). <br>2. Next remove the bezel and lens from the head and take out the factory reflector. <br>3. Insert the 800 lumen Firefly into the head. If you have a very old version of the Maglite you may need remove the extra set of rings that is on the base of the Firefly 800 first so it will sit deeper in the head, the set of rings will just slip off the bottom of the bulb. There are detailed ★PICTURES★ above in the product listing about the rings to help.  <br>4. Place the lens over the top of the 800 lumen Firefly reflector and screw the bezel back on to the head.  <br>5. Remove the retaining ring and bulb from the switch tower (if you have the bi-pin bulb you can press down on the tower to eject the plastic bi-pin bulb holder).  <br>6. Screw the head of the Maglite  back on to the body until it is "snug".</p><p>★★OPERATION INSTRUCTIONS★★:<br>In the PICTURES section above of the product listing there is a detailed set of TEXT instructions on how to operate the 3 mode user interface.</p>