The two basic types of plastics used for switches are polycarbonates and polysulfone. Polycarbonate, an opaque housing, requires slots to be cut to allow the light to shine through. This material is also impervious to many chemicals used in the assembly process. Polysulfone, the transmissive option, is used in dusty locations but care must be taken because many chemicals may damage it; furthermore, this device is more sensitive to ambient light.