Headphone Cushion For Sennheiser HD 350 BT / 4.40 BT/HD 4.50 BT/HD 4.50 BTNC / 458 BT Earpads | Protein Leather + Memory Foam | Replacement Headset Earpads (Black) | Crysendo | Reviews on Judge.me
New Headphone Case for Sennheiser HD 4.40 HD 4.50 BT HD 4.50BTNC Bluetooth Wireless Headphones Carrying Case Portable Pouch Box - AliExpress
Sennheiser HD 4.50 BTNC Wireless review: A worthy Bose competitor at a better price - CNET
Amazon.com: Sennheiser HD 4.50 BTNC Bluetooth Wireless Headphones with Active Noise Cancellation, Black and Silver (Discontinued by Manufacturer) : Electronics
Amazon.com: Sennheiser HD 4.50 SE Wireless Noise Cancelling Headphones - Black : Electronics