There is no single chemical formula for a wristwatch. A wristwatch is a complex object made up of many different materials, including:

* Metals: Steel, gold, platinum, alloys

* Glass or Sapphire: For the face and crystal

* Plastics: For cases, bands, and internal components

* Electronics: Circuits, batteries, transistors, etc.

* Leather or other materials: For bands

Therefore, a wristwatch doesn't have a single chemical formula. It's a combination of various materials and components.