New and improved tower extension. Now has 5mm thick walls and a 7mm thick base. It provides a good, snug fit and eliminates the "leaning" I was getting on my earlier versions. Position the base, temporarily clamp or tape in place to mark where the mounting holes go, and drill holes slightly smaller then your screws. Gently drive in your screws little by little, adjusting the position of the base as needed before tightening all the way. It is very sturdy.