Charm Fit-X Wireless Sports Headphones Charm Fit-X Wireless Bluetooth Headphones. Bluetooth Version: V5.3 Frequency Range: 2.4 GHz-2.48 GHz Operating Distance: 10 meters Battery Capacity: 3.7 V/120 mAh Talk Time: Approximately 15 hours Charging: Type-C port Charging Time: 2 hours Frequency: 20-20 kHz