Audioline M 4500. Display diagonal: 45 mm (1.77 "), Display resolution: 128 x 128 pixels, Display number of colours: Monochrome. Data network: GSM, GSM bands supported: 900, 1800 MHz. Headphone connectivity: 2.5 mm. Ringer type: monophonic. Battery technology: Lithium-Ion (Li-Ion), Battery capacity: 750 mAh, Battery recharge time: 2 h