The GS-111 Combination Inside - Outside Miter Fence is a must have for the GlideStop if your shop frequently cuts miters. You can use the Fence for tip-to-tip measurements, for example when producing mitered cabinet doors and for inside dimensions measurements when cutting picture or mirror frames.GS-111 set-up for tip-to-tip measurementsAs seen in the photo, the miter stop block can be secured in different locations depending on the work piece. This item accommodates inside, outside, and 90° cuts. the innovative dual sight gauge makes this possible, one line is for 90° and the other is for 45° cuts.GS-111 set-up for inside miter measurementsPlease note that the GS-111 Combination Inside - Outside Miter Fence is a "add-on" accessory and it is engineered specifically for the GlideStop. as such, it will not work on other stop systems or fence rails.