The short answer
Your red dot or scope flashes because sunlight hits the objective lens at an angle and bounces off the glass toward whoever is in front of you. A honeycomb killflash ARD puts deep, narrow cells over the lens, which block that off-angle light while you still look straight through.
When glare actually matters
Glare matters most when the sun is in front of you or off to one side and someone or something downrange could see the flash:
- Hunting. A glint from a stand or a glassing spot can give away your position to game that has already learned to watch for movement and light.
- Glassing with binoculars. Long sessions behind big 50mm objectives give the sun plenty of chances to catch the glass.
- Competition and training. Some shooters run an ARD to practice with the same setup they hunt or work with.
- The range. Honestly, most range days don't need one. If you shoot with the sun at your back and nobody is watching for a flash, you can skip it.
A killflash is a tool for specific conditions. Plenty of people never need one, and that's a fair call.
The clarity trade-off
A killflash isn't free. The cell walls sit between your eye and the target, so you give up a little:
- Brightness. The walls block some light. You'll notice it most at dawn and dusk, and least in bright midday sun, which is when glare is the bigger problem anyway.
- Field of view. Deep cells narrow what you see through the objective, especially when your eye isn't centered behind the optic.
- The look. On a red dot you may see a faint honeycomb pattern at the edges. Most people stop noticing it once they focus on the target, but some never like it.
Cell depth sets the balance. Deeper cells block glare from more angles but cost more light and field of view. Shallower cells keep more of the view but let more angled light through. We size each housing to the optic it fits rather than using one cover for everything.
Friction-fit or screw-mount
How an ARD attaches matters as much as the honeycomb.
- Screw-mount. Our HS510C / HE510C killflash mounts with the optic's original Holosun screws, so you don't need extra hardware and it stays put under recoil.
- Friction-fit. Our Romeo5 Gen 1, 56mm scope and Diamondback 10x50 ARDs press over the objective. They go on and come off fast, which helps if you only run one in the field.
Fit guide
Binocular ARDs and red-dot ARDs are different parts. A 50mm slip-on pair won't mount on an HS510C. Match the housing to your optic:
| SKU | Fits | Mount | Price |
|---|---|---|---|
| HS510C / HE510C | Holosun HS510C / HE510C only | Original Holosun screws | $19.99 |
| Romeo5 Gen 1 | Sig Romeo5 Gen 1 (not Gen II / XDR) | Friction-fit | $19.99 |
| 56mm scope | 56mm objective rifle scopes | Friction-fit | $24.99 |
| Diamondback 10x50 2-pack | Vortex Diamondback 10x50 (many 50mm objectives) | Friction-fit pair | $55.98 |
Not sure your optic matches? Ask us before you order. We'd rather answer a fit question than handle a return.
Install and care
- Clean the lens first. Blow off grit, then wipe with a lens cloth so nothing gets trapped under the ARD.
- Screw-mount (HS510C). Remove the original screws, seat the ARD, then reinstall the same screws snug. Don't overtighten.
- Friction-fit. Line the housing up square with the objective and press it on evenly until it seats.
- Check your view. Look through the optic and confirm the reticle or image is clear and centered.
- Care. Rinse dust out of the cells with water or a puff of air. Skip solvents, and keep the ARD out of a hot dashboard for long stretches.
More glare questions
We answer the most common questions about optic glare, from whether a killflash dims your dot to which optics we make ARDs for, in the optic glare FAQ on our killflash page.
Made in Gulfport, MS
Every Sentinel Outfitters ARD is printed and checked in Gulfport, Mississippi, and ships free anywhere in the US. See shipping and returns for details, or browse every housing on the killflash page.