Just how water-resistant is that box filled with electricity? Adrian Kingsley-Hughes/ZDNET I remember a time when you wouldn’t dare let water anywhere near a smartphone or power bank, as it would almost certainly mean disaster. Today, however, most smartphones are designed to be water- and dust-resistant to some extent, and even gadgets like power banks and portable power stations are following suit. Also: The best portable power stations you can buyBut how can you determine exactly how water- and dust-resistant a device is? And what’s the difference between something being water-resistant and truly waterproof? IP ratings explainedThis is where IP ratings come into play. IP, short for Ingress Protection, is an international standard used to measure a device’s resistance to water, dust, and other foreign objects. It’s expressed in the form of IPXX, where each “X” represents a numeral. The first digit indicates protection against solid particles, like dust, while the second digit measures resistance to liquids. The numbers for dust range from 0 (not dust-resistant) to 6 (dust-tight), while the numbers for liquids range from 0 (no protection) to 9 (protection against high-temperature, high-pressure water jets). Also: My favorite power bank for traveling is waterproof and surprisingly lightweightIf an X appears in the rating, that indicates unknown, meaning a test wasn’t carried out. For example, IPX5 means that no test was carried out for dust intrusion. IP RatingDust Protection (First Digit)Liquid Protection (Second Digit)XUnknownUnknown0No protection against dust or solid objectsNo protection against liquids1Protection against solid objects larger than 50 mm (e.g., hands)Protection against vertically falling water drops2Protection against solid objects larger than 12.5 mm (e.g., fingers)Protection against vertically falling water drops when the device is tilted up to 15°3Protection against solid objects larger than 2.5 mm (e.g., tools, wires)Protection against water sprays at an angle of up to 60°4Protection against solid objects larger than 1 mm (e.g., small wires)Protection against water splashes from any direction5Limited protection against dust (dust might enter but won’t interfere with operation)Protection against low-pressure water jets from any direction6Complete protection against dust (dust-tight)Protection against high-pressure water jets from any direction7N/AProtection against temporary immersion in water (up to 1 meter for 30 minutes)8N/AProtection against continuous immersion in water under conditions specified by the manufacturer (e.g., depth and time)9N/AProtection against high-pressure, high-temperature water jetsThis standardized system eliminates the ambiguity often caused by marketing claims, providing a clear and reliable measure of durability. More