The Manfrotto 620-10 – Male Adapter is a 1 1/8″ (28 mm) M10 Male Adapter that is often used to add a mount to the yoke of a heavy cinema light or accessory. The M10 screw slips through the hole in the yoke and is secured by the included wing nut. 
The 1 1/8″ stud is then inserted into a stand or similar piece of supporting hardware with a matching “Junior” receiver.