Sentry Pro Series Premium, Bluetooth, Rechargeable Wireless On The Neck Ear Buds, BT950. Includes: USB, On the neck folding ear buds, and extra pads. Earbuds are retractable with a push of a button. Pull the earbuds out when you want to listen to music and push the button for them to go back into place.
• Driver: 10mm
• Frequency response: 20Hz-20kHz
• Impedance: 32+/-3 Ohms
• Sensitivity: 100 +/-3 dB
• Rated Power: 150mW