Headphones & Earphones
Sennheiser HDR 175
Sennheiser HDR 175, Additional Wireless Headphones for System RS 175, Circumaural, Closed design, Maximum sound pressure level: 114 dB, Transmission range: 17 - 22000 Hz, Up to 18 hours operating time
https://www.bizrate.co.uk/headphones_earphones/sennheiser-hdr-175-oid10304784955.html