Sure Shot 521 Heavy Duty Basketball UnitUpgraded and redeveloped to an even higher specification, the Sure Shot 521 is a portable, heavy duty basketball unit designed for schools, colleges and leisure centres. The unit features a larger and stronger UV and weather resistant backboard made with fibreglass composite. The 521 can be easily moved around using the mounted wheels, and it can be filled either with 130 litres of water or 210kg (463lbs) of sand to ensure proper ballast, stability