For mobile phones, IP Code is an international standard that classifies and rates the degree of protection provided against dust and water. Each IP code consists of the letters IP and some xy designation, for example IP57. The first digit after the prefix denotes dust-resistance and ranges from 1 to 6. The second digit denotes the phone’s water resistance and ranges from 1 to 8. The most durable phones on the market are labelled IP68 – they are fully waterproof and dustproof, so you can submerge them to a certain depth for a time specified by the manufacturer.