Hold-down Plate/Bed Limiters: Bed Limiters, or holddowns as they are also called, are used to limit the packing bed from moving and getting packing pieces entrained away from the bed. They are secured to the wall or loosely placed on the packing;they are made of rods and bars or in combination with screens or expanded metal, depending on the application. Hold-down plate can be made in various metals and plastics.