What is a cake tester?

Could you elaborate on the concept of a "cake tester"? Is it a tool specifically designed for baking? If so, what purpose does it serve? Does it have a specific design or material that sets it apart from other baking utensils? Additionally, are there any special techniques or considerations to be aware of when using a cake tester? I'm curious to understand the significance and practical application of this tool in the baking process.