GPX13 13W. 13 Watt UV Pond / Aquarium Sterilizer Bulb , Lamp GX23 Base Produces UV-C (253.7 nm wavelength) radiation Non-chemical approach to disinfection; Fits the GX23 base and has two molded snaps Used in : Fishmate Filter 3000, Amilair BEUV RB-13 sterilizer,13W Aquarium Reef Jabo Jebao UV GX23