Honoring the ordinary that makes life extraordinary

Simple inventions but doing wonders

There are alot of humble and simple tools/products that have affected and still affecting humanity wonderfully. Doing wonders but very simple and common some of which are everyday use equipments.
Some of this tools (products) are capitals as they are required to do business. This proofs how simplicity always drives exceptional progress.

Example of simple invention but doing wonders

KNIFE.. As simple as a knife is I guess it is clear the wonders that this invention/tool is doing everyday. From the kitchen to the industry. Helps in cooking of food that human beings cannot do without for so long. The economic impact and importance is real.

Let honor this tools
 What other tool(s) is a simple invention but doing wonders in human life and what wonders is it doing?
What's the economic impact and importance?