Sharp IR range finders are pretty popular sensors, but I usually see them externally mounted and directly exposed to the environment which makes them prone to being damaged or getting crufty.
I have a few that I'd like to use on an outdoor rover, and I'd like to cover them with some sort of transparent case to protect them dirt and impacts in the environment. What type of plastics would be completely transparent to these sensors, and where would I buy simple sheets of it?