Same Problem, Same Light, Hunter 25
I had the same problem several years ago. These are Perko Lights (to my knowledge this style is no longer in production) which, as pointed out by John Geiger, can be special ordered through Boat US. However, a local store had them in stock and, at the time, had several sets of lenses in stock (don't remember the price but they came as a set of both the red lens and the green lens). I am enclosing the store's name and address, in case you run into any problems with Boat US (I had no luck at all with our local West Marine). Try Mike's Marine Supply, 24910 Jefferson, St Clair Shores, MI 48080, phone (810) 778-3200.