Sennheiser HD 4.40 BT, Over-Ear Wireless Bluetooth Headphones - Black | eBay
Replacement HD4.50BT, HD4.50BTNC, HD4.40BT Memory Ear Pads Cushion Compatible with Sennheiser HD 4.50BT, HD 4.50BTNC, HD 4.40BT Bluetooth Headphones - Newegg.com
NeweggBusiness - Sennheiser HD4.40 BT Bluetooth Wireless Headphones
Amazon.com: Geekria Sport Cooling Gel Replacement Ear Pads for Sennheiser HD4.50BT HD4.50 HD4.50BTNC HD4.50SE HD4.40BT HD4.30G HD4.20S HD458BT HD450 HD450BT HD400S HD350BT Headphones Ear Cushions (Black) : Electronics