The kit is very similar to the well known XTM panels and snaps on in the exact same way, except for the large backstop, which requires a hex wrench for installation. The kit comes with 1 standard fullsize XTM panel, a halfsize XTM panel, a modded fullsize XTM panel with low profile stop (the frontstop panel), and the large backstop (which requires the screw).
Installation
I started the process by installing the low frontstop with the idea that everything else would fall into place behind it. This panel simply snaps into place. As pictured below, the pieces are combine, but not fully locked into place, prior to attaching them onto the rail. This makes it a lot easier to snap them into place once you have the XTM panel in position on the rail.
Finding The Right Spot
With the frontstop panel in position, a fullsized XTM panel was dropped in behind it. I then started toying with the placement of the large backstop. The options I was personally addressing for fit were: option 1, my 4 fingers fall in between the large backstop (which is not screwed in yet, notice open hole on nut) and the frontstop or, option 2, three fingers falling in between the large backstop and the frontstop, with my index finger falling in front of the frontstop.
A 3rd option is to only use the large backstop, which I had no intention of doing, thus, no pictures. A potential 4th option would be to just have the frontstop on the rail.
Be sure to test out your options with gloves on if you do run gloves while shooting. Following are pics of option 1 with all four fingers falling in between the two handstops.
Next are pics of the 2nd option I was looking at with my index finger falling in front of the frontstop.
Once you finalize the fit, tighten down the screw with a hex wrench. Do not overtighten, it is not necessary, especially because most Magpul screws come with a factory loctite application. If you want to apply some additional loctite, feel free to do so.
One additional feature to note on the panels is that they come with small clips that allow you to snap a wire into place, in this case, the wire for a Surefire Scout light. If you intend to utilize the clips, be sure you lock the panels into place with the clips on the correct side for your light. The wire on the M300B installed on this firearm is only 5" long, so I did not use the clips on the XTM panels, but a very thoughtful and useful feature to note.
Final notes. I went with option 2. Magpul, a badass American company that makes great stuff.