A snap hook is a type of metal hook that is commonly used in a variety of applications, such as sailing, boating, camping, hiking, and other outdoor activities. Snap hooks are typically made from materials such as stainless steel or aluminum, and are designed to be durable and resistant to corrosion.

Snap hooks are named for their design, which features a spring-loaded gate that allows for quick and easy attachment and detachment of ropes, straps, or other equipment. The gate can be opened by pulling back on a small lever or pin, which releases the tension on the gate and allows the rope or strap to be inserted or removed.

Snap hooks come in a range of sizes and shapes, and can be selected based on the specific needs of the user and the application. They are often used to secure gear to a backpack or belt, to connect ropes or cables to an anchor point, or to attach a safety line to a harness.

When using snap hooks, it's important to ensure that they are rated for the weight and load of the equipment being attached, and to inspect them regularly for signs of wear or damage. It's also important to use proper techniques when attaching and detaching equipment, and to follow all safety guidelines and instructions.