ASUS ZenFone 2 ZE551ML 4GB RAM / 64GB ROM 5.5-Inch 2G / 4G Dual SIM Factory Unlocked International Stock No Warranty (Gray/Silver) Dual-SIM : 3G WCDMA 850 / 900 / 1900 / 2100 ; 4G FDD-LTE 2100MHz(1) / 1900MHz(2) / 1800MHz(3) / 1700MHz AWS(4) / 850MHz(5) / 900MHz(8) / 700MHz(28) ; 4G may not work in the US, 3G works with AT&T ; LTE compatibility: This is international stock, varies per carrier (ensure to check with your carrier before purchase); DOES NOT work with Sprint, Verizon, U.S. Cellular and all other CDMA carriers. 64GB ROM, 4GB RAM, Supports microSD up to 128GB Intel Atom Quad Core Z3580 (2.3 GHz), PowerVR G6430, with OpenGL 3.0 support