The Gray Pressure Plate is a variant of Pressure Plate, characterized by a gray top. It is used as a switch, and may be connected via Wire to other mechanical items. Whatever it is connected to will be activated when the switch is stepped on by a player. These can be found in Dungeons and underground sometimes connected to various traps, which is often more viable than purchasing them from the Mechanic. File:Terraria - Red Wire Traps Tutorial Terraria HERO