QCell Sprint Samsung Epic 4G / S pro 3650mAh Extended Battery + Free Battery Cover (NOT Compatible with D710 Epic 4G Touch) Epic 4G Extended Battery! Highest Capacity in the Market! Designed in Canada! Double Your Battery Life with this High Capacity Battery! Comes with Free Battery Cover! DYNAStop overcharge IC stopper built in! Voltage: 3.7V / Premium Quality and Best Material used!