When buying used phones off of eBay, Craigslist, or the like, a primary concern of anyone purchasing CDMA devices (Verizon, Sprint, Boost Mobile, Virgin Mobile, etc.) is the status of the phone's ESN (electronic serial number). If a device's ESN is registered as "banned" on its carrier because it has been listed as stolen or is attached to an unpaid account, then that phone cannot be activated on said carrier. Thus, the phone is either useless or has to be activated on a pre-paid carrier, which is generally not all that desirable and drastically decreases a device's worth. Update: JCase... Official Android Police t-shirts are now on sale, with over 25 designs to call yours.Done With This Post? You Might Also Like These:[Exclusive] TacoRoot By Justin Case And Reid Holland: A New Temporary Root Exploit For All HTC Devices[Exclusive] How To Easily Root The Amazon Kindle, Regardless Of Its Software Version[Updated: Watch Out!] On-Phone One Click Root Available For Samsung Galaxy SHTC Droid Eris On-Phone One Click Root AvailableBest Buy Launches Free Phone Fridays To Start Your Weekends Right[Update: Free Version Now Available] New App: Quickly Get Info About The Status Of A Phone's ESN With PocketESN was written by the awesome team at Android Police.