This sight is 2.6” long. No footprint mentioned is at least 2.6” long. The pic mount is 2.6” long. Where is the 2.6” long footprint for pistol mount?! — 1 Answer

From the website:
RD3-011 Avenger (5 MOA RED Dot). The overall length is about 30% longer than other traditional handgun red dots, the window is 100% bigger than traditional micro red dots. Therefore, it does NOT fit an optics ready pistol that has a cut. Unlike other Ade RD3 models that have doctor footprint, RD3-011 has the same screw pattern/footprint as trijicon rmr. This sight does not fit (sit inside the grove/cut) the slide that is custom milled for trijicon rmr because it is longer than rmr in size. It only fits mounting plates that replace the rear sight, or the plate set above the slide for trijicon rmr footprint/screw pattern. Top battery loading, no need to remove the red dot from the firearm when changing the battery.