Aquatop 13 Watt UV replacement bulb compatible with the following Aqua top products: FZ13 Canister Filter with UV Sterilizer SP13-UV Internal Filter with UV Sterilizer UVP-13 Submersible Pump UV Sterilizer UVCP-13 Submersible Pump UV Sterilizer UVFK-13 Submersible Pond UV Sterilizer with Pump + Fountain Kit UV Sterilizing Pump UVE13