Noise cancelling Earbuds

CX 300-II Precision Black

Get a powerful, dynamic sound with big bass response in a stylish, custom-fit ear canal phones. An asymmetrical cable provides freedom of movement and the included carrying pouch avoids tangles in transit.
$ 59.95
plus applicable sales tax – free shipping
Article No. 502737
★ ★ ★ ★ ☆ 4.1
32 Reviews


Offering a powerful, bass-driven stereo sound with greater clarity and improved dynamics over standard earbuds are the CX 300-II ear-canal phones. The various sizes of ear adapters (S/M/L sizes) provided in the package allow for a customized fit as well as exceptional noise blocking capability.


  • High-quality dynamic speaker systems for bass-driven stereo sound and durability

  • Personalized fit in the ear canals functions as an earplug and high-quality speaker

  • Customizable ear adapter system achieves the perfect fit

  • Convenient carrying pouch included

  • Asymmetrical cable reduces tangles and cable clutter

  • Built-tough with a 2 YEAR warranty!

  • **Important wearing note! The longer side of the asymetrical cable goes behind the neck and into the opposite ear. This mimics a single sided cable and reduces the amount of cable in front of the wearer during physical activity. This is a safety and ergonomic feature. Please contact Sennheiser with any questions about product fit

  • Only purchase from an authorized dealer.

  • Compatible (listen only) with latest generation of tablets

What's in the box?

  • CX 300-II ear-canal phones
  • Ear adapter set (S/M/L)
  • Carrying pouch

Technical Data

  • Color
  • Wearing style
  • Impedance
    16 Ω
  • Frequency response (Headphones)
    19 - 21000 Hz
  • Sound pressure level (SPL)
    113 dB
  • Jack plug
    3.5 mm
  • Cable length
    1.2 m
  • Transducer principle
Reviews (32)
4.1 of 5 ★ ★ ★ ★
  • Mike the Golfer
    Las Vegas
    Finally, ear buds with base!

    Simply put these are the best ear buds I have ever owned and the price is a steal for the performance you get. They deliver a deep rich base that will not leave you disappointed. I have owned Sennheiser products before, but these headphones take the cake. A frequency response of 19,000 to 21,000 Hz? Unheard of and exceptional.


    Base Done Well, Compact, Durable, Stylish, Comfortable, Great Sound, Good Value, Lightweight



    Portable Devices, Working, Relaxing, With My Computer, Traveling, Music


    I would recommend this to a friend.

  • Nick

    Good bass for earbuds. Obviously can't expect the same bass from over-ear headphones or a subwoofer, it just doesn't work that way. They sound perfect to me. I'm no audiophile or professional in any way, but I can say they're the nicest earbuds I've ever had the pleasure of listening to. Occasionally I have a problem with them falling out of my ears when I smile, but that's with any earbuds I've owned. These will be no different in that department if you've had the same experience (maybe I'm just weird). Fit comfortably, can wear them for HOURS without them feeling uncomfortable (10 hour night shift, no sore ears). I can turn my device to almost silent and I'll still hear almost no ambient noise. The design seems flimsier than previous earbuds I've owned, but as long as you don't abuse them, they seem to be doing perfectly fine. No issues so far after a couple months of use. Overall, no real complaints. Extremely happy.


    Great Sound, Comfortable, Good Bass



    Working, Music


    I would recommend this to a friend.

  • Jake
    Xenia, Ohio
    CX 300-II Precision headphones

    I wear them at work and I am completely satisfied with them. Wouldn't want any other kind!


    Good Value, Stylish, Durable, Great Sound, Compact, Lightweight, Good Bass, Comfortable



    Traveling, Working, Music, With My Computer, Portable Devices


    I would recommend this to a friend.


  • Foam Ear Adapters

    A good source for foam ear adapters for the majority of Sennheiser ear bud models is a company called Comply Foam (

    CX 300-II ( #502737 )
  • Why is one ear bud cable is longer than the other?

    Some ear buds models (like the CX 300-II) feature cables where one side of the cable is longer than the other. These are called "asymmetrical" cables and is a deliberate design by Sennheiser.

    The longer side of the cable goes behind the neck to the other side of the head and into the ear so instead of having a two cables hang in front of a user in a "Y" configuration an asymmetrical configuration only has one single cable that is off to the side where it is out of the way.  It is recommended to route the cable above the ear and then down into the ear canal.  The cable exiting the ear bud should be pointing up.

    CX 300-II ( #502737 )


  • High Resolution Images
    • Hi Res Image CX 300-II (Black) (100 KB) Download

    • Hi Res Image CX 300-II (Silver) (870 KB) Download

  • EU Declaration of Conformity
    • EU Declaration of Conformity (620 KB) Download

WARNING (for California residents only): This product can expose you to chemicals including lead, which is known to the State of California to cause cancer and birth defects and other reproductive harm. For more information go to: