From adult to youth play in 60 seconds…ZipCrank corner mount rim height adjusters are designed to avoid reduced backboard and rim rigidity common with other height adjustable goal systems • Movable framework slides up and down on two chrome plated 1" diameter rods riding in machined steel bushings • Height adjusters are installed between the backboard and the backboard support structure and when retrofitted on existing courts moves face of backboard 4¼" toward the free throw line • May require minor field drilling on some existing retrofit applications • Adjusts rim infinitely from official 10' to 8' heights and includes easy-to-read height indicator labels • Operated with the hand crank provided or with optional BA931 Cordless Winch Winder • Rim height adjusters are not warranted for dunking or hanging by adults • See chart for ordering details including use on center strut structures • Five-year limited warranty..