While IP (Ingress Protection) ratings are more commonly used for electronic devices like smartphones and cameras, they can also be applied to watches to indicate their resistance to water and dust. An IP rating consists of two digits, with the first representing protection against solids and the second representing protection against liquids. In general, a higher second digit signifies better water resistance. However, watch manufacturers typically use ATM or depth ratings to indicate water resistance, making it essential to understand both systems when selecting a watch.