Sennheiser CX 400BT True Wireless review: A battery that just doesn't give in - Neowin
Sennheiser CX 400BT True Wireless Earbuds - Bluetooth In-Ear Headphones for Music and Calls - with Noise Cancellation and Customizable Touch Controls, White
Best Buy: Sennheiser CX 400BT True Wireless Earbud Headphones Black CX400TW1 Black