wifi. A Carrier: The coolpad surf is for T-mobile and only work with the T-Mobile wireless network. LED Indicators: Power, Wi-Fi, SMS, Battery, Data Consumption 2,150 mAh Battery Standby Time: Up to 48 Hours Usage Time: Up to 5.3 Hours LTE Charging Time (Full Charge): Up to 2.5 Hours Processor Type: MDM9207 Processor Speed: Single-Core 1.3GHz OS: Linux 3.18 IP Rating: IP52 Memory: 256MB ROM / 128MB RAM Expandable Memory: N/A