Product review (1 stars): Worst design ever for a splash guard.
This comes standard on the InSinkErator Evolution.  It is simply the worst design I can imagine.  The hole in the middle is only 1/2 inch in diameter.  Water does not even flow through this.  Pushing waste paste it is almost impossible.
I tried the "InSinkErator RSB-OO Removable Sound Baffle" from Amazon, as a replacement, and it works perfectly. (it measures 3.375 inches in diameter)