Unlocked cellphones are compatible with most of the GSM carrier ( Like T-Mobile or AT&T ) but please be aware that are not compatible with CDMA carriers ( Like Sprint or Verizon Wireless for example ) 128GB + 8GB RAM - NM (Nano Memory), up to 256GB (uses SIM 2) - Non-removable Li-Po 4200 mAh battery - Hisilicon Kirin 980 Octa-core 2.6GHz