Sennheiser CX 6.00BT and HD1 Free: a tale of two headphones - The Verge
AKG N200 Wireless vs Sennheiser CX 6.00BT: What is the difference?
Amazon.com: Sennheiser Consumer Audio CX 6.00 BT Wireless in-Ear Headphones, Bluetooth 4.2 with Qualcomm Apt-X, 6-Hour Battery Life, 1.5 Hour Fast USB Charging, Multi-Connection to 2 Devices, Black : Electronics