The Plate of Hatter is an item in Silent Hill. Its purpose is to open the door at the back of nurses' center in the Otherworld of Alchemilla Hospital, and is located in room 204 on the 2nd floor of the facility.
The plate is on the floor of a hospital room, guarded by a Bloodsucker drinking from a puddle of blood. Harry Mason must toss a blood pack to the side of the beast to redirect it so the path to the plate is unguarded.
John Tenniel's illustration is the source of inspiration for the plate picture.