What is a double purchase counterweight system?

A double purchase counterweight system is designed to provide a mechanical advantage by requiring less weight on the arbor than the actual weight being supported above the stage. In this scenario, for every 1 pound of weight located over the stage, 2 pounds of counterweight on the arbor is needed. This system allows for greater efficiency and control in handling heavy scenic elements and reduces the physical demands on stagehands when adjusting and rigging those elements.

The design of a double purchase system means that the user can safely lift heavier loads without needing to match the weight directly on the arbor. This is particularly useful in theatrical settings where safety, space, and operability are paramount. The other choices do not accurately capture the characteristics or workings of a double purchase counterweight system, focusing instead on other configurations or not accurately representing the fundamental mechanics involved.