H2O Wireless 2-in-1 (Dual) SIM Card can be used as either a standard-sized SIM or as a Micro-sized SIM card. Compatible with most smartphones such as Samsung Galaxy series, HTC, LG, and any Apple iPhone 4S and below should be compatible with this SIM card. For Apple iPhone 5 and up, please use H2O 3-in-1 (Triple) SIM Card. This SIM card comes fully equipped with H2O's unique features such as : 1. "smart" technology to automatically configure H2O data settings once plugged into your phone 2. "direct dialing" which eliminates you from memorizing your H2O international calling access number and then its PIN number. All of that is already pre-programmed on the SIM.