Holosun HS507K X2 review: the carry micro, red or green

By the OpticVerdict Editorial Team.
Research-based review · Updated 2026-08-19

How we reviewed it: a research-based review built from the retailer specification sheet, the verified owner-review record across both the red and green models, and a deep-research pass. We have not bench-tested this unit ourselves; the score is our editorial opinion and owner ratings are shown attributed to their source. See how we evaluate.

What it is

The HS507K X2 is Holosun's subcompact carry red dot: a 1x open reflex sight on the Holosun K footprint, sized for slim pistols like the SIG P365 family, the Glock 43X and 48, and the S&W Shield Plus. It weighs 1 oz, seals to IP67, and packs the features Holosun is known for into that tiny body, a Multi-Reticle System, Shake Awake, Lock Mode and a 50,000-hour battery, without the polymer housings or bottom-loading batteries that used to be the price of going this small.

The circle-dot is the reason to buy it over a plain dot

The Multi-Reticle System is what separates the 507K from its cheaper 407K sibling and from most carry micros. Hold a button and you cycle three ways to aim: a precise 2 MOA dot on its own, a 32 MOA circle on its own, or the two combined as a circle-dot. On a defensive draw from concealment, when your hands are not perfectly indexed, the big 32 MOA ring acts as a funnel that pulls your eye to the center dot faster than hunting for a bare dot. It has a second benefit too: shooters whose astigmatism makes a plain dot smear or starburst often find the larger, softer circle far easier to read. The 407K gives you a plain single dot in the same housing for less; the 507K is the one to buy if you want that ring.

“This optic has the larger dashed ring which makes finding the red dot much faster. Much more forgiving if your gun draw is slightly off. Also has the shake awake feature and auto shutoff. Great optic for my PSA Rock.”

tau, verified owner (TX), via OpticsPlanet

Red or green: the HE507K-GR variant

Holosun builds this sight in red as the HS507K X2 (around $300 ) and in green as the HE507K-GR X2 (around $320 ), and the two are otherwise the same optic. The choice is your eyes: many shooters acquire a green dot faster in daylight and against dark targets, and green often reads more cleanly than red for astigmatism, which is a big part of why the green model has drawn 250 verified reviews to the red's 90. The green carries a small premium, a few percent rather than a tier; pay it if you pick the dot up faster, and take the red if you do not. Reticle is a second axis, not just colour: both models also come with Primary Arms' chevron-and-ring ACSS Vulcan reticle in place of the standard one, for under $400 in either colour, so the real choice is a two-by-two rather than a straight red-or-green. All four were in stock when we checked. We weigh emitter colors generally in green dot vs red dot and best red dot for astigmatism.

The side battery tray, and the footprint catch

Two mounting-and-power details define daily life with this optic. The good one: the CR1632 loads from a tray on the side, so you change it without unbolting the sight, and you never lose your zero to a battery swap, a real upgrade over the bottom-loading micros it replaced. The catch: to make the housing IP67 waterproof, Holosun tweaked the standard RMSc footprint, so while it drops straight onto a SIG P365X or XL, a Glock 43X or 48 MOS and other four-boss slides need an adapter plate. That plate raises the optic, which often lifts it above your factory iron sights and means buying taller suppressor-height sights if you want to co-witness. Check your pistol's cut before you order.

“The Holosun HS507K seamlessly integrates with the SIG Sauer P365X... Installing the HS507K on the P365X is a breeze, thanks to its user-friendly mounting system that ensures a secure fit without any modifications required. The low-profile design maintains a slim profile that facilitates comfortable holstering and concealed carry.”

ace, verified owner (CA), via OpticsPlanet

What owners flag, plainly

Across 339 combined reviews the 507K is very well liked, and the complaints are the honest limits of a small open-emitter carry optic rather than a pattern of failures. The open emitter collects lint and dust inside a waistband holster, so you will occasionally blow out the emitter well to keep the dot crisp. There is no solar failsafe, so the battery is your only power. And the small, recessed buttons that resist accidental presses in a holster are hard to work with gloved hands. One owner reported a battery lasting only about two months, but he noted he had seen no other reviews like it and suspected a lemon, so we read that as an isolated unit rather than the norm.

“My battery only lasts about two months... I don't see any reviews like this, so maybe I got a lemon.”

Most helpful negative review (an isolated report), via OpticsPlanet

Trade-offs, plainly

• Open emitter, so the well can collect lint, dust and debris on a carry gun and needs occasional cleaning. For a sealed sight, step up to the enclosed Holosun EPS Carry.
• Popular slides like the Glock 43X/48 MOS need an adapter plate, which raises the optic and can put your factory irons too low to co-witness.
• No solar failsafe, so the CR1632 is the only power source; there was no room for a solar panel at this size.
• The recessed buttons are deliberately small to resist holster presses, which makes them hard to work with gloves.
• A small 0.58 x 0.77 in window: it is a carry-micro sight, not a full-size optic like the 507C.

Key specifications

On awards: the 507K itself has no standalone industry award, and we checked. Holosun the brand and adjacent models have won plenty (Holosun took NASGW Optics Manufacturer of the Year), but none of those trophies was given to the 507K, so we claim none. What it has instead is one of the deepest owner-review records of any carry micro: 340 verified reviews across the red and green models.

Should you buy it, and what else to consider

• Buy it for a slim carry pistol (P365 family, Glock 43X/48, Shield Plus) if you want the fast circle-dot, a zero-saving side battery and proven toughness in the smallest footprint.
• 407K or 507K? The 407K is the same sight with a plain dot instead of the circle-dot, for less money. We settle it directly in Holosun 407K vs 507K.
• 507K or 507C? Same reticle system, bigger window, full-size slide. Read the HS507C-X2 review if your pistol is not a carry micro.
• Save money with the plain-dot HS407K-X2 if you only want a simple dot and not the circle. See Defender-CCW vs HS407K-X2.
• Step up to the enclosed Holosun EPS Carry if you want a fully sealed emitter for daily carry and can accept a little more size.
• Mounting a Glock? The plate decides as much as the sight. See best red dot for a Glock.
• Carrying a Sig P365? This is our top pick for that slide; see the whole RMSc field in best red dot for a Sig P365.
• Want a full-size dot for a duty or range pistol instead of a carry micro? See the HS507COMP and our best red dot sight guide.

FAQ

More: best red dot sights · best pistol red dots · best red dot for a Glock · Defender-CCW vs HS407K · Holosun HS507COMP review.