Tracfone - Bring Your Own Smartphone- Nano Sim Kit - At&t Towers New Product from Tracfone - Bring your Smartphone to Tracfone !! Transfer your Tracfone Service to a AT&T or unlocked GSM Phone. Nano Size Sim Card Only - Need to purchase minutes or transfer them from your current Tracfone.. Works off AT&T Towers via Tracfone service..