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 • Manual models are operated with the hand crank provided or with optional BA931 Cordless Winch Winder • Electric models operate with hard wired wall mounted  • See chart for ordering details including use on center strut structures • Five-year limited warranty.