RETRAC convex mirrors add safety and functionality to heavy-duty trucks, semis, buses, utility vehicles and more. They offer versatility in their application and tested quality. This round convex mirror head features 5" diameter convex glass to provide a wide-angle view of the vehicle's blind spots and the passing lane. It is constructed from strong carbon steel and features a durable black powder coat finish to provide a sleek, professional accent on any heavy-duty truck. This convex spot mirror is also thoroughly tested to ensure long-lasting durability, undergoing both a vibration test and a 360-hour salt-spray test. It installs using a 5/16" center-mount ball stud, providing extra strength to reduce vibration, and the ball mechanism allows for simple adjustment to locate the ideal angle for each particular application (J-bracket and mounting assembly not included).