SIM card reader USB version 2.0 standard, compatible with USB version 1.1 Sim card reader can read GSM sim card Twoslots for card reader and one slot for sim card reader Data transfer rate: up to 480Mbps Supports Cards: Mini SD Card,Micro SD(T-Flash),SD,MMC,MMC Plus,RS-MMC(MMC Mobile), MMC Card 4.0,RS-MMC 4.0(MMC Mobile 4.0),Sim Card Plug-and-play and hot swapping USB bus-powered Supports Windows 98SE, 2000, Me, XP,Vista & Mac OS 9.0 Product size: 8.85 x 3.1 x 1.35cm