PCB (printed circuit board) mounting enclosures are a piece of equipment used to store and protect printed circuit boards. They can provide an aesthetically pleasing PCB cover for the board, while still allowing you to interact with it when needed.
Printed circuit boards are often very delicate pieces of hardware, which means they need to be safeguarded against external conditions where possible. By putting them inside a mounting enclosure, you give the circuit board additional protection against external contaminants as well as accidental damage or breakage. A PCB mounting enclosure also lends a more finished look to the device.
PCB mounting enclosures predominantly vary by size and material. Your choice will depend on the type of printed circuit board you are planning to store. Many PCB mounting enclosures are made from some type of metal, as this kind of enclosure offers more robust protection than their plastic counterparts.