A popular modular lens extension for use with many longer length zoom lenses the extension threads onto the base of either the modular 8 inch dome or the modular glass flat front for simple assembly and use in a wide variety of applications accommodates lenses up to 425 inch 108 cm long and 33 inch 84 cm in diameter when used with the modular 8 inch dome accommodates lenses up to 415 inch 105 cm long when used with the modular glass flat front measure your lens or use the port fi