Rosco's patented "Rebound Technology" allows the mirror arm, not the mirror head to be hit upon inadvertent contact with obstructions. Rebound springs the arm back in its original place when the vehicle moves away from the obstruction. Mirror head comes standard with an acrylic unbreakable convex lens which provides clear views behind the vehicle. Rebound auto-return technology allows the mirror head to always remain properly adjusted for safe and effective rear cross viewing.