We used the flat lens instead of a bubble lens to make it blend better with the solar panels. Bubble lenses gather more light.
Entrance pipe:
Half done:
Installer Richard Wimmer of Blue Ridge Home Improvement: 
We used ~16' of pipe that included five 0-45° elbows.
We used ~16' of pipe that included five 0-45° elbows.
Completed installation:
It lights up a dark stairway.