This former sits inside on the front side of the fuselodge hatch flange. You will need to watch the angle on these because the wing pins slide through the fuse in this are. You can tell where these pins go through by looking at the outside of the fuselodge wing area. You have a pin, 1" wingtube and another pin that need to be drilled out. I believe the pins were 5/16" k&s aluminum tubing. I used the dremel with a small router bit to cut out most of the area where the 1" wingtube slides through. There is a sandwiched piece of wood ply in the wing area with a 1" hole cut into it. When you get most of this are cut out, slowly trim it out just up until you hit the ply. When you are done you should have a 1" hole that the wingtube slides into.