The Studica Robotics T-Slot Extrusion is available in 10 different lengths from 48mm to 1000mm. It is strong, while light-weight. It can be easily cut to your own custom size. It has a 14mm through hole that will fit the Studica 6mm ID x 14mm OD Flanged Bearing or Bronze Bushing It uses the M3 T-Slot Nut Hammer Head Series 20.  It also has four M3 threaded holes on each end. Can be used as structure with infinite applications.