A popular modular lens extension for use with many shorter 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 35 inch 89 cm long and 33 inch 84 cm in diameter when used with the modular 8 inch dome accommodates lenses up to 34 inch 86 cm long when used with the modular glass flat front measure your lens or use the port finde