Large 40mm Drivers Two advanced dynamic speaker drivers provide superb high-fidelity stereo sound with deep bass response. Experience the fullness of your music and hear more than before. You’ll also get more complete & compelling sound while watching movies and videos Longer playtime Keep your music playing from morning to night with a 2.5-hour charge of the large 500mAh lithium-ion battery. Switch from Bluetooth to wired mode using the 3.5mm audio cable to continue listening if the battery runs out True Comfort Super-soft memory foam earpads and adjustable headband ensure optimal fit with reduced pressure for a comfortable listening experience Specifications Chipset: 8763BFR Driver (each channel): 40mm / 1.57\" speaker driver Speaker Frequency Range: 20Hz - 20kHz Speaker Sensitivity: 117dB ±3dB Speaker Impedance 32 ohm ±15% Microphone Sensitivity: -40dB ±3dB Microphone Frequency Range: 50Hz - 16kHz Input: DC 5V Charging Time: 2.5H Battery life: up to 25H Battery type: Li-Polymer (500mAH) Operating range: Up to 10m / 33ft Weight: 220g Box contents 1 x AUKEY EP-B52 Over-Ear Wireless Headphones 1 x USB-A to C Cable 1 x 3.5mm Audio Cable 1 x User Manual