New Mercury, Mariner Thermostat KitThis kit will fit the following Four Stroke models:9.9hp 1999 - 2004 0P075166 - 0P32549915hp 1999 - 2008 0P75166 and up (will NOT fit models after 2006 serial number starting 0R_____)25hp 1998- 2005 0P075166 - 0P40099 (not EFI models)30hp 1999 - 2005 0P017000 - 0P400099 40hp 1999 - 2020 0P017000 and up50hp 1995 - 2000 0G231123 - 0T178499If you have any doubts whether these will fit your outboard, please email your model and serial number.These are OEM parts, not aftermarket/pattern itemsThank you for looking.