This product will speed up the process of running a rack of conduits on a piece of strut if you're running 1/2" to 1" trade size EMT conduit or you're running 3/4" or 1" trade size HW conduit. You measure and level your first conduit on your rack and then depending on what size conduit you're running you use the appropriate spacer to maintain an even spacing between every conduit on your rack of pipes 1/2" and 1/2" EMT spacing is 1.5", color black 1/2" and 3/4" EMT spacing is 1.5", color blue 1/2" and 1" EMT spacing is 1.5", color clear 3/4" and 3/4" EMT spacing is 1.5", color orange 3/4" and 1" EMT spacing is 1.75", color red 1" and 1" EMT spacing is 2", color white 3/4" and 3/4" HW spacing is 1.5", color translucent aqua 3/4" and 1" HW spacing is 1.75", color translucent blue 1" and 1" HW spacing is 2", color translucent red