This 3.5" ID Wall Eye Wall Port gives the user a fully tubed opening through a wall or other barrier that has a thickness range from 4" - 6 1/2". The unit installs in a recommended 4 3/8" diameter hole. The outside flange on this unit is 5" in dimeter, which helps to hide any imperfections that may occur while making the hole to install this unit. This unit can also be produced in Grey or Black with an additional 2 days shipping time requirement or any other custom color with an additional 2 week shipping requirement.