Wireless head-band headphones DEFENDER Freemotion B651 — binaural, closed acoustic, 20–20000 Hz, 105 dB, USB-C, AUX

DEFENDER Freemotion B651 are wireless head-band headphones with a binaural design and a closed acoustic system. They provide a frequency response of 20–20,000 Hz and a sensitivity of 105 dB. The headset supports wireless connectivity and also offers USB‑C and AUX‑in ports for charging and wired connection. The product is intended for universal everyday use; do not disassemble or modify the device.

Advantages

The closed acoustic design reduces external noise for clearer playback, while the head-band binaural construction ensures stable fit and even sound distribution across both ears. USB‑C connectivity enables modern charging and quick connection, and the AUX‑in option allows continued use when a wired connection is preferred or required. The headphones cover the full typical audible frequency range and offer high sensitivity for pronounced sound output.

Suitable for

• Listening to music and podcasts
• Hands-free phone calls and voice communication
• Watching videos and other media playback
• Everyday portable use at home, office, or while commuting

Key specifications

• Wearing style: head-band
• Headset type: binaural (stereo)
• Acoustic system: closed
• Frequency response: 20–20,000 Hz
• Sensitivity: 105 dB
• Connectivity: wireless with AUX-in
• USB input port type: USB‑C

How to use

Place the headphones on your head so the ear cups fully cover your ears and adjust the head-band for a comfortable fit. Use the wireless pairing procedure described in the device manual to connect to a Bluetooth source, or plug an audio cable into the AUX‑in port for a wired connection. Charge the device via the USB‑C port using a compatible charger until the battery is full. Follow on-device controls to play/pause audio, adjust volume, and answer calls.

Usage recommendations

Do not disassemble or modify the product yourself. Use the supplied connectors and follow standard charging practices. Keep the headphones dry and avoid exposing them to extreme temperatures to preserve performance and lifespan.