Flush valve replacement for a Toto

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?

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

Thank you!

Thanks for the prompt reply. Much appreciated!