The Samsung Galaxy S II (GT-I9100) is a smartphone running the Android operating system that was announced by Samsung on February 13th, 2011, at the Mobile World Congress. It is the successor to the Samsung Galaxy S, with a different appearance and significantly improved hardware. The phone is also the predecessor of the Samsung Galaxy S III. The Galaxy S II was one of the slimmest smartphones of the time, mostly 8.49mm thick, except for two small bulges which take the maximum thickness of the phone to 9.91mm.
The Galaxy S II has a 1.2 GHz dual-core "Exynos" system on a chip (SoC) processor, a WVGA Super AMOLED Plus screen display and an 8-megapixel camera with flash and 1080p full high definition video recording. It is one of the first devices to offer a Mobile High-definition Link (MHL), which allows up to 1080p uncompressed video output to an MHL enabled TV or to an MHL to HDMI adapter, while charging the device at the same time. USB On-The-Go (USB OTG) is supported.
The user-replaceable battery on the Galaxy S II gives up to ten hours of heavy usage, or two days of lighter usage. According to Samsung, the Galaxy S II is capable of providing nine hours of talk time on 3G and 18.3 hours on 2G.
Samsung Galaxy S II specs on Phonearena.com.