These two slides show the extent and types of information recorded in the NSA’s DNR (phone record) database. Selectors specified include Location Area Code (LAC), Cell Tower ID (CellID), Visitor Location Register (VLR), handset serial number (IMEI) and full phone number (MSISDN): see the Washington Post article NSA tracking cellphone locations worldwide, Snowden documents show, 4 December 2013.