nIMEI
nInternational Mobile Equipment Identity, a unique number given to every single mobile phone, typically found behind the battery.
nIMEI numbers of cellular phones connected to a GSM network are stored in a database, Equipment Identity Register, containing all valid mobile phone equipment. (To have IMEI, press *#06#)
nIt is a 15 digit number:
tttttt-mm-ssssss-a448902701569710
ntttttt : 6 digit Type Approval Code
nmm : 2 digit Manufacturer Code
nssssss : 6 digit Serial Number
na : 1 Additional digit, usually 0