A French cleat is a popular method for hanging items on walls securely. It consists of two pieces of wood/metal or whatever sturdy material you are utilizing, each with a 45-degree bevel cut along one edge. One piece is attached to the wall, and the other is attached to the item being hung. The beveled edges interlock, providing strong support.

People use French cleats for several reasons:

1. Strength and stability: French cleats distribute weight evenly, making them ideal for hanging heavy items like cabinets, shelves, and mirrors.
2. Adjustability: Items hung with French cleats can be easily adjusted horizontally to ensure they are level.
3. Versatility: French cleats are adaptable and can be used for a variety of applications, including hanging artwork, tools, and kitchen utensils.
4. Aesthetics: The cleat itself is often hidden, giving the appearance that the item is floating on the wall.

Overall, French cleats provide a reliable and flexible solution for wall mounting, particularly for heavier or more substantial items.