You can use a Fluidmaster 400A for the Toto models that use the ball cock (fill valve) by Coast.
For the Toto toilets that don't use a "ball cock",
those use the Korky Quietfill.
The Korky Quietfill will also replace the Mark 1V
I have a Toto toilet with a Master Mark IV flush valve that needs to be replaced - I have been unsuccessful in locating an exact replacement online but have been told that the Fluidmaster 400A is a correct replacement for this item.
Does anyone have any thoughts about this? Is there another manufacturers equivalent out there I should consider before picking up a Fluidmaster unit?
Thanks for the prompt reply. Much appreciated!