It is convenient to put in cables of PC, telephone FAX, printer etc etc in a bundle. This duct goes through the corner of the desk, but it can be placed a little on the cover, and it has surprisingly not been short of space.
Easy to install because the screw hole is open. Lid is easy to remove. Price is high. Improvement points (benefits depending on circumstances?) Are easily slidable, so that they are pushed by cables or the like and misaligned when vertically mounted.