4208BC, 1/2" x 1/16" x 72", Aluminum, Mill Channel, Designed For Trim Work, Frame Work & Reinforcement Projects, Often Used To Fit A Plywood Edge Where The Plywood Thickness Matches The Channel Width Dimension, Channel Width Dimension Is The First Size Specification Listed In The Size Column, & Is A Fraction, Aluminum Is Light Weight, Yet Strong, Withstanding Heavy Pressure & Loads, Aluminum Can Be Bent Or Formed Into A Multitude Of Shapes.