This will mill your standard frame size Glock (eg., G17, G19, G26) for the Sig Romeo 1 Pro. This service will NOT work with the standard Sig Romeo 1 red dot. This should allow you to use the included sheet metal guard, and there are recoil studs. Because of the length of this red dot, it will remove the rear dovetail, but the Romeo 1 Pro has an integrated rear sight. The top of the red dot base will sit 0.260" above the top of the slide without the sheet metal guard, allowing it to cowitness with the Dawson 0.260" tall front sights, pictured here. With a sheet metal guard the height will be 0.300" above the top of the slide. The slide will be tapped for the M4x0.7 screws which come with your red dot. Some fitting of the screw length may be required if you are installing this red dot yourself.