This will allow you to mount the Trijicon RMRcc on your Sig P365 without any mounting plates. This program allows you to keep your factory rear dovetail, so you can cowitness with iron sighs. The top of the red dot base is roughly .225" above the top of the slide, so you will need sights at least that tall to see them through the red dot. The Trijicon RMRcc does not have openings for the typical 'recoil lugs,' and as such there are none in this slide milling. Your red dot will be held in by a snug machined fit in the slide, and the two screws. These screws are also unusual, being 5-48 threads, and we will mill your slide to accept those screws. If you send your optic and sights in we will mount and align them for you.