Sennheiser CX400-II-B In-Ear Headphone with Dynamic Speaker System and Integrated Vol Controls (Discontinued by Manufacturer)
Sennheiser CX 400BT review | What Hi-Fi?
Sennheiser CX 400BT True Wireless Earbuds - Bluetooth In-Ear Headphones for Music and Calls - with Noise Cancellation and Customizable Touch Controls, Black
Sennheiser CX 400BT True Wireless Earbuds - Bluetooth In-Ear Headphones for Music and Calls - with Noise Cancellation and Customizable Touch Controls, White