TOTO Fill Valve Extension and Adaptor for Washlet Tee Connection - 9AU321-ATOTO Fill Valve Extension and Adaptor for Washlet Tee Connection 9AU321 Necessary to install any washlet on Aquia IV two piece and Connelly two piece models This WASHLET adapter and thread extender is designed for use with select TOTO toilet models that require fill valve extension. This adapter has a 7 8 inch fill valve connection to extend the threads when access to the fill valve is limited. Connect the female end of the adapter to your fill valve