Volkano Impulse Series Bluetooth Headphones - Red - Bluetooth Wireless Headphones - Walk and Talk - Micro SD Card Reader - Line-in Mode - FM Radio Specifications: - Input Voltage: 3.7 5V - Bluetooth Version: V4.0 - Transmission Distance: 10M(approx. 33 ft) - Battery Capacity: 250mAh - Transmission Frequency: 2.45GHz - Charging Time: 70min - Supporting Operating System: IOS, Android - Minimum Rated Talk Time: 8 hours - Support: FM/TF Card - Minimum Rated Standby Time: 250 hours - Battery Type: Lithium Ion