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maintenance 1


In short, keep your threads and o-rings clean and lubricated if you want to maintain optimal performance for as long as possible.

All mechanical systems require regular maintenance to function properly. A flashlight is not exception. We get plenty of warranty claims that are from a lack of maintenance. Save us both some trouble!

Failing to properly maintain your light is like buying a car and never changing the oil. We sell (and recommend) Nano-Oil for lubricating o-rings and threads. It works great and has been extensively tested for o-ring compatibility. It’s the only thing I use on my lights.

> How to clean & maintain threads

Quick cleaning (head and body):
  1. If your threads aren’t terribly dirty you can just use a DRY paper towel and/or Q-Tip to wipe down the threads.
  2. You don’t want to use cleaning fluids unless you must.
  3. Dirty threads can cause premature wear and inhibit the flow of electricity, leading to erratic behavior of the light.
  4. Allow parts to dry completely before reassembly.
  5. Reapply a light coat of oil. A few drops will suffice.
  6. Do not oil internal threads, only apply oil to external threads.

Deep Cleaning (head):

It’s critical that you don’t introduce moisture or oil into the electronics.

  1. Start with a dry toothbrush or Q-tip to remove the bulk of the contamination.
  2. If your threads are gritty and/or gunked up (from lack of maintenance naughty you) I like to use Simple Green, rubbing alcohol, or Windex (something that cuts grease & evaporates quickly).
  3. Put a small amount of cleaning solution on a Q-Tip or paper towel. Try to press the swab (or towel) into the threads to get down into the grooves.
  4. Allow parts to dry completely before reassembly.
  5. Do not oil internal threads, only apply oil to external threads.

 Deep Cleaning (body):

  1. Normally I use a toothbrush for this. The body does not contain any electronics, so feel free to get after it.
  2. I still recommend an evaporating cleaner.
  3. Allow parts to dry completely before reassembly.
  4. Reapply a light coat of oil. A few drops will suffice.

Special Note - Alpha Flashlight Head threads: 

  1. There is a tight fit between the driver mount and the head threads, so it requires a special technique.
  2. Take a Q-tip and mash the end flat with a pair of pliers. This will allow the Q-tip to fit between the threads and the copper post that holds the LED driver.
  3. Run the Q-tip clockwise several turns and then back it out counter clockwise.
  4. If you use a cleaner, allow parts to dry completely before reassembly.


  1. Optics people call that front glassy thingy the light shines through a "window," not a lens. Be careful when you clean it because it has a special anti-reflective coating.
  2. If you get too aggressive you can damage it. I actually use my hot breath and camera lens papers. Some solvents may damage the coating, so I prefer not to use any.

> How to clean & maintain o-rings

Spare o-rings are included with all Prometheus and Foursevens flashlights. You probably won't need them, but if the main seal ever breaks or tears, you'll have a replacement on hand.

A dry o-ring will become cracked and/or otherwise damaged during normal use. A lubricated o-ring will not. Damage will compromise water resistance and make your light difficult to operate.

Petroleum based lubricants should not be used because it will damage the o-ring. WD-40 is NOT a lubricant. It is a lubricated cleaning solvent...do not use it :)

  1. If your o-ring is dry and not dirty, you can just reapply a couple drops of oil. Enough to get smooth operation, but not so much that it drips everywhere. Excess oil attracts dirt…that you’ll have to clean later.
  2. For a full cleaning, simply remove the o-ring and clean as needed, being careful not to rip the o-ring with excessive force.
  3. An o-rings that is visibly damaged should be replaced. An o-ring does NOT need to be replaced unless it is damaged.
  4. Reapply a light coat of oil. A few drops will suffice.
  5. Reinstall the o-ring making sure it is not A twisted o-ring does not seal well and will accelerate damage.