We all know that Ikea stuff is really cool and fits in almost all cases. But in real life things are not always as perfect as hoped for, as I noticed when I had the challenge to mount the Kvartal curtain track rail to my wall, which had a small ridge making it impossible to mount the rail securely. So I designed this little piece to fill the gap between the backplate and the wall and printed 4 of them on my Ultimaker-2 and mounted the curtain rail securely to the wall. The design is made to fill a gap of approximately 14,5 mm, if you want to fill another gap please scale this design in the z-axis direction only to get the required height in Cura or the slicing software you are using. For example: if the gap is 8mm, scale the design 8/14,5 = 55% in the direction of the z-axis.