The most critical use case for this keyword is . If you are buying an iPhone from someone on OfferUp or Swappa:

To check your device's IMEI or serial number, simply follow these steps:

Before we dive into the "how," let's explore the "why." Millions of iPhones are sold on secondary markets like eBay, Craigslist, and Facebook Marketplace every year. Unfortunately, many of these devices come with hidden problems that aren't visible to the naked eye.

Find the serial number of your Apple product - Apple Support (IN)

: Verify if "Find My" is active. A device locked to a previous owner’s Apple ID is effectively a "brick" and cannot be used. Authenticity

Some IMEI checks will tell you if the device is a "Replacement Unit" (Apple swapped it out). While not bad, it affects resale value because the serial number won't match the original box.