Stack - Weight
a pile of weight plates drilled so that they can slide vertically on poles, most often two fixed solid rods and one moveable rod with a series of holes along its length, with a horizonal hole or gap in each plate such that a pin may be inserted through the hole or gap in the plate and into a matching hole in the moveable rod. This weight and all those above it may then be lifted by the moveable rod, which is typically attached to a cable or lever arm.