Doctors are firing back at critics who are questioning the safety of Robert Kraft's PPE mask donations this month ... slamming the hate and straight up calling the charity "a godsend."
If you missed it ... after Kraft got his Patriots plane to deliver over 1 MILLION masks from China to the U.S. -- some questioned the effectiveness of the pieces.
The Boston Globe -- citing several medical professionals -- claimed there was concern that a version of the N95 mask -- known as the KN95 mask -- that Kraft negotiated for wouldn't be good enough to protect medical personnel in the States.