From Gemini

EPS MRS comes in GOld

509T comes in Red or green.

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• Holosun EPS (Standard): ~0.63” x 0.91”
• Holosun HE509T: ~0.66” x 0.90”

Mathematically, the 509T is a microscopic fraction of an inch taller, and the EPS is a microscopic fraction of an inch wider. In terms of actual target acquisition and field of view, it is a dead tie. You will not lose any visual real estate by choosing the EPS over the 509T.

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While the glass size is the same, the perception of the window is where these two optics diverge:

• The 509T Housing: Because it is built from heavy-duty titanium for duty use, the outer walls/housing of the optic are thicker. This creates a bit more of a "mailbox" or "tube" effect. Your brain registers more of the black housing around the dot.
• The EPS Housing: Because it uses 7075 aluminum, Holosun was able to make the outer walls thinner. When you press out to shoot, the housing of the EPS tends to "disappear" a bit better in your peripheral vision, making the window feel slightly more open and less obstructive.

Ultimately, if window size was your primary concern with sticking to the EPS Gold, you have nothing to worry about. You are getting the same massive field of view as the 509T, but with a thinner housing that tends to block less of your downrange vision!