The HD1 Free In-Ear Bluetooth Headphones from Sennheiser are designed for a mobile lifestyle, with Bluetooth 4.2 and Qualcomm aptX for hi-fi sound. They can be used with smartphones to take and make phone calls or control music with up to 2 devices at once, and also support 3-way calling.
Featuring a neckband wearing style, the headphone's ear pieces are magnetic so you can join them together and wear them comfortably around your neck when they are not in use. You can also carry them in the included leather carry case.
The HD1 Free headphones have a frequency response of 15 Hz to 22 kHz and feature custom machined, stainless steel in-ear sound tunnels. The lithium-ion battery provides about six hours of listening time, and an included USB cable lets you recharge the headphones. Also included is four sets of eartips in four different sizes (XS, S, M, L), ensuring a snug and secure fit.