Mustang M31. Display diagonal: 45.7 mm (1.8 "), Display: TFT. Maximum memory card size: 8 GB. Data network: EDGE, GPRS, GSM, GSM bands (primary SIM): 850, 900, 1800, 1900 MHz, GSM bands (secondary SIM): 850, 900, 1800, 1900 MHz. Ringer type: MP3, Audio formats supported: MP3, MP4. Battery technology: Lithium-Ion (Li-Ion), Battery capacity: 650 mAh, Standby time (GSM): 120 h