What is the fine-grained topic of the following text: A covert earpiece is often referred to as either a surveillance earpiece or invisible earpiece and it is quite common for the likes of law enforcement officers on undercover assignments, security personnel, government agents, and also spies, both corporate and government to wear such a device while undertaking tasks that require privacy and secrecy. Only return the topic.
Use of covert earpieces in law enforcement and espionage