WOW, that is a grea price!
I have a 176c. I don't have any problems reading it in bright sunlight. I have mine mounted on top of the dash with the power/data cable running down through a hole in the top of my dash. Then I have the data cable connected to my GPS speedo. It works great. I can push a little lever, unhook the cable and remove from the dash when I dock the boat somewhere. I have no trouble reading it while underway.