The Joker has a non-angled 12-point beak, therefore it requires just 30° of working space, otherwise it functions just like a regular open end wrench. The dark metal plate dual functions as a retainer, preventing the nut to slip through the wrench beak or it holds the nut. 30° further the metal retainer plate allows the nut to slide through, or grip it since the metal plate is equipped with a hardened ragged edge. The teeth of his edge will 'bite' itself into a rounded-off nut, loosening it where others do nothing but slip-off. Color coded for size. Size: 30mm/32mm. Overall length: 305mm.