If your carry gun is a slim pistol and you are tired of wiping lint out of an open emitter, this is the one to look at. It is the enclosed micro Holosun: P365, Hellcat, Glock 43 or 48, and similar slides. Same idea as the full-size EPS, in a narrower body. The LED sits behind a sealed window. You still get the circle-dot, a 2 MOA dot, a 32 MOA circle, or both, plus solar backup and a side-loading CR1620.

It weighs about 1.23 oz. The window is about 0.77 × 0.58 in, smaller than a full-size EPS. That is the trade. You give up a little glass so the dot still shows up after the gun has lived in a holster. If you want this footprint with an open emitter, the 507K is that optic.

The footprint is Holosun K, and the box includes an RMSc-to-K plate for four-lug slim cuts. If the slide is already milled for K, leave that plate in the box. The optic sits lower, and it lines up with the sights the slide was cut for.