For perform student experiment about mechanical efficiency.

Made of aluminum and with metal frame, with hooks on top and bottom. Diameter: 50mm.

①    Single pulley, Diameter: 50mm

②    Double tandem pulley: Diameter: 40mm/ 50mm

③    Double parallel pulley: Diameter: 50mm

④    Triple tandem pulley: Diameter: 30mm/ 40mm/ 50mm

⑤    Triple parallel pulley: Diameter: 50mm

⑥    Quadruple parallel pulley: Diameter: 50mm