Sennheiser's CX 400BT are its most affordable true wireless earbuds yet | Engadget
Sennheiser brings its top-notch sound quality to less expensive true wireless earbuds - The Verge
Sennheiser CX review: Better than CX 400BT?
Amazon.com: Sennheiser Consumer Audio Sennheiser CX 400BT True Wireless Earbuds - Bluetooth In-Ear Headphones for Music and Calls - with Noise Cancellation and Customizable Touch Controls, Black : Everything Else
Amazon.com: Sennheiser CX 400BT True Wireless Earbuds - Bluetooth In-Ear Headphones for Music and Calls - with Noise Cancellation and Customizable Touch Controls, White : Everything Else