A popular modular lens extension for use with many of the longest zoom lenses including the nikon 18 35mm 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 51 inch 129 cm long and 33 inch 84 cm in diameter when used with the modular 8 inch dome accommodates lenses up to 5 inch 127 cm long when used with the modular glass flat front measure you