When sitting it on my workbench and granite countertop I measured a 1/32 inch gap in the middle of the track. Dont open the package indoors! I do order from this brand as much as I can, but I was very disappointed today when I received my Yes4All Tricep Rope. i have not use the slippers at all. Beep one and they all go off. Do recommend. The application was easy. ?? A light duty bike carrier. However just make sure to get a size smaller than normal.