Built-in microphone. Noise isoloation. Folding design. 8 hrs playtime. Built-in microphone. Great sound. Folding design. Works with mobile. Noise isoloation. Deluxe Headband: Soft cushioned. Headband. Great Sound: Full-range dynamic. Studio sound. Deluxe Earpads: Soft cushioned. Studio-grade earpads. Folding Design: Travel friendly. Folding headband. Bluetooth 5.0: Wireless headphone with control buttons. Built-In Mic: Talk on the phone with hands-free microphone. Driver: 40 mm. Frequency: 20HZ-20KHZ. Playback: 8hr (at) 50%. Battery: Li-Ion. Range: 30ft/10m. Charging: USB (included). Bluetooth: Version 5.0. Actual playback times may vary. Battery performance may be affected by multiple factors including but not limited to ambient temperature, listening volume, and/or distance from the source audio device. Driver: 40 mm. Playback: 8hr(at)50% volume. Frequency: 20hz-20khz. Battery: 3.7v (lithium-ion). Impedance: 32 +/-3. Range: 30 ft/10 m. Sensitivity: 100 db+/-3 db. Charging Time: 2-3 hours. Power: 16 mw. Charging Cable: USB (included). Bluetooth: 36 db. Bluetooth: version 5.0. Limited 90-Day Warranty: Sentry warrants this product to be free from defects in materials and workmanship for 90-days from the date of original purchase. This warranty does not pertain to damage resulting from an accident, abnormal use, misuse or neglect. Any defective product will be replaced if returned to an authorized Sentry dealer or to Sentry Directly at: PO Box 885, One Bridge Street, Hillburn, NY 10931. Please enclose a $5 check for return shipping. CE listed. www.sentryindustries.com. Made in China.