I would recommend finding one locally. It does not need to be a special dome. Any dome will work, ceramic is better than plastic, but for a UVB bulb that puts off no heat, plastic will definitely work. If you want, you could even paint the inside of it white Im sure, and "boost" the UVB efficiency. A white surface IS better for reflecting light than a shiny metal surface. Im am not sure if that applies to UVB though...although I would assume so.