A snap hook is a type of fastener commonly used in various applications, such as climbing, sailing, and securing gear. It features a spring-loaded gate that allows for quick attachment and detachment, making it convenient for users. Snap hooks are typically made from materials like stainless steel or aluminum, providing strength and durability. These hooks come in different sizes and designs, including carabiners and lobster clasps, to suit specific needs. They are often used in outdoor activities, such as rock climbing and hiking, as well as in everyday items like keychains and dog leashes.