Yucurem 3.5mm to 2.5mm Audio Cable Wireless Headset Cord for Sennheiser HD4. 40BT - Walmart.com
Amazon.com: Sennheiser Consumer Audio HD 4.40 Around Ear Bluetooth Wireless Headphones - Black : Electronics
Any giveaways to the authenticity of these HD 4.40bt headphones that can be seen from these pictures? Bought from AliExpress (Yeah I know but if they are fake they are free). :
Sennheiser HD 4.40BT Wireless Headphones Review - YouTube