Allows closeup view of nozzle and print as it is formed on print bed. A sliding arm allows user to determine view desired. A large printed knob allows easy adjusting. Works with most cams with nut in base to secure it. 

It is easy to attach to the left front x rail, using the same design as the sidebox. It can be inserted, removed, adjusted while printing is in process without causing an interruption. I have tried others, but none work near as well as this model.

Designed in Fusion360, and sliced with PrusaSlicer. Used Prusa orange PETG for effect, but not necessary. No supports, brims, supports needed.