As the names suggest, the key difference between the two is the addition of NoiseGuard active noise cancellation on the 4.50BTNC. While Sennheiser isn't talking pricing yet, we expect that extra feature means they will be slightly more expensive.

Both the HD 4.50BTNC and HD 4.40BT use Bluetooth 4.0 and AptX to ensure high-quality sound with the addition of NFC to make pairing a breeze. The two models will also keep the music going for up to 25 hours before needing to recharge. As you might expect, employing active noise cancellation cuts battery life to 18 hours on the HD 4.50BTNC. We will have some more detailed impressions when we get our hands on the headphones later this week.

Sennheiser's popular Momentum line gains a new member with the wireless HD 1. The halo-style earbuds use Bluetooth 4.1, AAC and AptX and carry a similar look to previously released Momentum in-ear headphones. There's a handy three-button remote on the neckband for controlling music and taking calls on the go. You can also expect 10 hours of battery life here and the HD 1 is expected to ship this month. Like the new HD headphones, Sennheiser isn't talking price with the new Momentum device just yet.