I bought a Dubby miter sled two years ago at a wood show (great product). Using it for polygons with long sides, frames etc. was no problem I thought the miters were spot on. However when I started cutting very small pieces the closure was very very close but not perfect. Jerry Cole advised me to watch this video. It solved the problem completely for me. My cuts are now near perfect every time. The problem I was having was when the segments became so short that I was relying on the wooden sacrificial block on the Dubby miter bar. If it was not near perfect in line with the miter bar then angles could be off ever so slightlly. This add on fence eliminates that problem. I thought some of you who use the Dubby sled would benefit from it if you were not aware of it. It really solved one of my biggest problems in my segmented project.