A fastener is a screw-threaded metal fitting that is used to mechanically secure one thing to another or to attach some object in place.
They work on the basic screw thread locking mechanism. It consists of a male and a female part, the male part is supplied with the external thread, while the female part is supplied with the internal thread. Collectively, they form the basic locking structure that a fastener needs to operate.
Ring hook fasteners are used to mount ceiling fans. Structurally it consists of a metal ring with a rawl bolt attached to the end. It inherits the ability to get affixed to mounting surfaces in such a way that it can withstand the load of associated heavy objects. After installation, only the ring part is visible through which the ceiling fan is suspended.