July 26, 2021

Spotter Up

In Depth Tactical Solutions

Thyrm CLENS Weapon Light Lens Protector

If you shoot a lot with a weapon light attached to your firearm, you have encountered an annoying problem. Carbon buildup from muzzle blast eventually begins to fog up the lens. After as little as a box of ammo, the lumen output of a weapon light can be significantly degraded.

Thyrm CLENS applies easily to the lens of the weapon light or flashlight. It is optically clear and will not affect light output or beam pattern. Once the CLENS becomes fouled, you simply pull it off and replace it with another.

If you shoot during the day, you may not notice that the buildup is taking place until you try to use your weapon light at night or in a low light scenario. In addition to degrading output, the buildup can degrade and discolor the lens over time. It’s also a pain to clean off completely and is time consuming.

Various improvised solutions have been employed to in an attempt help mitigate the problem. These include taping up the lens or wiping gun oil, Vaseline® or lip balm on the lens. All of these improvised solutions leave much to be desired.


Thyrm®, LLC, an innovator in tactical and wilderness products, has a solution that’s both simple and practical. Called CLENS®, it’s a revolutionary lens protector that was developed in collaboration with Aaron Cowan of Sage Dynamics/Sage Instruments

CLENS (pronounced “cleanse”) had its genesis in low-light training conducted at Sage Dynamics. Aaron Cowan, Founder and Lead Instructor of Sage Dynamics states, “We noticed the degradation of light output as a student progressed in a low-light class. They often struggled to get the light’s lens clean and that process took them out of the class for a period of time. We knew that this was the answer.”

So what exactly is CLENS and what makes it unique? CLENS is a heat-resistant, clear polymer circular tear-off lens protector for weapon lights and tactical flashlights. It’s similar in concept to the tear-off visor and goggle protectors used by off road racers.

Once it becomes fouled up you simply peel it off and replace it with another CLENS protector. There is no risk of damage to the lens, which would be the case if using abrasive lens cleaners. It’s a very simple, cost effective solution. Not only does it protect your light, it allows you to clean the lens more effortlessly.

CLENS is designed to be durable and not be blown off by the muzzle gas from a muzzle brake. During the prototype phase they utilized a bunch of different materials and thicknesses to determine a design that, within reason, was going to stay affixed to the lens. The resulting design has withstood thousands of rounds fired.

When CLENS first came out it was only available in sheets that had multiple sizes of lens protectors. Thyrm now sells the CLENS in three sizes in addition to a variety pack. Each CLENS sheet includes 18 lens protectors.

Thyrm CLENS comes in a sheet of 18 lens protectors that are available in three sizes to fit a wide variety of weapon lights and tactical flashlight lenses.

Thyrm has a CLENS size chart on its website, showing the four models of CLENS sheets and the corresponding count and sizes of CLENS on each sheet,. It should be noted that the listed lights on the size chart are are only those that Thyrm has tested CLENS on for compatibility. CLENS will fit other similarly sized lenses.

To apply the CLENS, first unload and check your firearm, then clean and dry your weapon light or tactical flashlight lens per manufacturer’s instructions. Peel off appropriate sized CLENS from the sheet. Center and apply it to lens, applying pressure from one side to the other to remove air bubbles and wrinkles.

When the CLENS becomes fouled, simply peel it off the lens. The mild adhesive on the CLENS is designed to securely attach the CLENS yet leave no residue on a clean or undamaged lens.

The adhesive may stick to a dirty or damaged lens, but if this should occur, touching the sticky side of CLENS to any residual adhesive should remove it from the lens. Although designed for training, CLENS has obvious tactical applications in the field to protect the lens not only from carbon fouling but from dirt and debris, as well.

Thrym does caution that “although designed to withstand sustained firearms use, CLENS is constructed of polymer and may melt in the presence of excessive heat/flame.” This won’t occur with normal use, including high round count training and real world scenarios

To Sum Up

CLENS is a great product. It’s simple and effective a solution to a very real problem. One wonders why no one thought of it before. MSRP runs from $10.99 to $14.99 depending on the diameter of the CLENS protector. They’re available directly from Thyrm.

Material Disclosure

I received this product as a courtesy from the manufacturer so I could test it and give my honest feedback. I am not bound by any written, verbal or implied contract to give this product a good review. All opinions are my own and are based off my personal experience with the product.

*The views and opinions expressed on this website are solely those of the original authors and contributors. These views and opinions do not necessarily represent those of Spotter Up Magazine, the administrative staff, and/or any/all contributors to this site.

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