LENOVO BLUETOOTH HEADPHONE HD800 PTM7C02371 Heavy-Calibre Driver Speaker Senior Earmuffs IOS Electricity Display Volume Tactile Player/Pause/Play Answer/Hang up __________________________________________________ Bluetooth version: V5.0 Battery capacity: 500mah Play time: Approximately 20 hours Standby time: Approximately 300 hours Horn diameter: 40mm Speaker sensitivity: 103±3dB(IEC711 At 1 kHz) Frequency response range: 20-20kHz Distance: 10m barrier-free Wearing method: Head-mounted Product color: Black, Red Executive standard: GB/T 14471-2013