This typhoon reel system is made of heavy duty resins that take a beating and look great. The large wheel design rolls over virtually any surface for easy roll away storage. The crank mechanism is engineered with pinch roller bearings to provide smooth, effortless cover roll-up with crank handle on both ends for easy one person or two-person operation. Tube kit are pre-drilled for easy installation. It is recommended to use 4-inch tube kit for pool 600-square feet and larger or when using thicker mil solar blankets.