Spalding NBA 68395R Portable Basketball Hoop with 54 Inch Polycarbonate Backboard Backboard Shape: Rectangular / Square-- Rim: Arena Slam Rim--Heavy-duty solid steel rim with ultra smooth spring action. Pole Shape: Square--Provides added strength Pole Pad--Helps to prevent accidental injuries. Height Adjustment System: Screw Jack Lift System--Provides infinite height adjustment from 7.5 to 10 feet.