Round 2-3/8″ tenon adapter to slip over a 3 inch steel pole. When you are adding more fixtures your pole or just making your light adjustable, this needs to be your starting place. Slip this over the top of the light pole, make sure it is all the way down and tighten the bolts down. With the 2-3/8 tenon now on top of the pole, you can begin to add the pole mount backets that you have decided that works best for you. Call for custom tenon sizes.