The is a highly-rated prepaid option at Best Buy , specifically designed for unlocked GSM phones . It functions as a 3-in-1 universal kit (Standard, Micro, and Nano sizes) and provides access to the AT&T network without a long-term contract . Product Overview: H2O Smart SIM Kit
Utilizes LTE coverage; users often cite "same great coverage" as major carriers at a fraction of the cost .
Works with almost all unlocked GSM phones , including iPhones (4 through recent models) and Android devices .
