GLI 55-0000CY-BK Cyclone Inground Pool Solar Reel Resin System Base Kit Cyclone reel system is made of heavy duty resins that take a beating and look great The innovative offset frame design prevents tilting and the unique roller wheels recess into reel body for stationary operation The crank mechanism is engineered with pinch roller bearings to provide smooth, effortless cover roll-up with crank handle 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