refers to a watch’s ability to withstand exposure to water without damage. It is measured in meters (m), atmospheres (ATM), or bars, indicating the depth or pressure the watch can endure. However, these measurements are theoretical and don’t always equate to actual diving depths. 30m (3 ATM): Splash-proof, suitable for everyday use but not for swimming. 50m (5 ATM): Safe for showering or light swimming. 100m (10 ATM): Suitable for swimming and snorkelling. 200m+ (20 ATM or more): Ideal for professional diving or water sports.