Ikelite Extended 4.25" Body 5510.24 with 8" Dome 5510.45 - Package 5511.4 The injection molded acrylic 8-inch diameter dome is specifically designed for underwater photography to provide superior optical performance Domes are ideal underwater for shooting wide angle lenses This kit includes our Modular Lens Extension for lenses up to 4.25 inches (10.8 cm) in length (product number 5510.24). The Lens Extension threads onto the base of the Modular 8-inch Dome for simple assembly.