This small inside galley light lens is only 3" diameter at the base and 1-1/2" high. It is very rare as it was used on 1978 Airstreams.  Airstream has discontinued this part.

Please note: Our diffusers are in excellent condition but have some discoloration from sitting on a shelf for years. They were obviously nested together on the shelf in the Airstream factory and the lower half has darkened more than the top half. The issue is minor but we thought you'd like to know in advance.