As the Lighthouse Keeper for the month of Sept. here in Crescent City,CA (Battery Point)we have in custody a 4th order Fresnel which has a total
height of nearly 7'. I drove over to the museum
in town that houses the 1st order lens from St George Reef Lighthouse, I almost shed a tear at it's beauty and workmanship! I secretly moved the lens with all it's weight with one finger! Awesome. Don't miss it if you are in the area.