One of the smallest parts in your watch, and also one of the noisiest: The Pallet Fork.
The Pallet Fork is one part of the escapement in a watch movement. It is the key connection between the balance wheel and the escape wheel.
It is the interaction between the escape wheel and the pallet fork that creates the familiar ‘Tik, Tok’ sound that you hear when holding the watch close to your ear.
As you’ll have noticed, the pictured pallet fork is shaped like an anchor, an escapement using such a pallet fork is typically called an anchor escapement for that simple reason. The pink elements are Jewels and are the bits that actually get in contact with the escape wheel.