Pro-Quality tamper proof tennis system includes posts, tensioning hardware, nets, adjustable filler-panels, and features a unique net-tightener that is fully enclosed to prevent tampering or vandalism. Our exclusive "Net Guard" adjuster is the heart of this system. The mechanism is completely enclosed and permits positive net tightening that absolutely will not slip. There are no protruding pulleys or wheels. The ratchet action adjuster is accessible only to authorized personnel.