Sennheiser CX400BT True Wireless In-Ear Earbuds

Discount 11% List price: £140.83
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Powered by Sennheiser’s leading audio technology, the new CX 400BT True Wireless gives you total control over an exceptional sound experience. With passive noise cancellation, intuitive customizable controls, long-lasting battery life and a design made for all-day comfort, they are the ideal uncompromising choice for people that are passionate about great sound.

The bespoke drivers of the new CX 400BT True Wireless deliver high-fidelity sound with deep bass, natural mids and a clear, detailed treble. You can also personalise your listening experience with built-in equalizers to enjoy amazing sound quality that is tailored to your ear.

Regardless of whether you roll with iOS or Android, you will always get to enjoy the outstanding sound quality of the new CX 400BT True Wireless earbuds. Sennheiser always support a wide range of audio codecs, including SBC, AAC and aptX, so premium sound is guaranteed with any mobile device.

The new CX 400BT True Wireless earbuds are designed to ensure you get premium sound wherever you go. With 20 hours of battery life available - 7 hours on a single charge and a further 13 hours with the small, sleek and compact charging case.

Available in black and white, CX 400BT have an ergonomic design created for all-day comfortable wearing. The earbuds achieve a perfect fit in the ear for excellent passive noise cancellation and keep the earbuds securely in place, thanks to adapters (included) in a choice of four sizes.

You can also gain further control over your sound with Sennheiser Smart Control - a free app, compatible with most iOS and Android systems. Available in 8 languages including German, English, French, Spanish, Russian, Korean, Japanese and Mandarin.


  • Passive noise cancellation
  • Built-in equalizers
  • Up to 20 hours battery life
  • Charging case included
  • Earbud-mounted touch controls
  • Bluetooth 5.1
  • Further functionality via free Sennheiser Smart Control App


  • Dimensions: 59 x 33.8 x 42.3 mm (earbuds and charging case)
  • Weight: 49 g (both earbuds and charging case) 6 g (single earbud) 37 g (charging case)
  • THD: < 0,08% (1 kHz / 94 dB)
  • USB Standard: USB-C
  • Warranty: 2 years
  • Frequency Response (Microphone): 100 Hz to 10 kHz
  • Bluetooth Version: Bluetooth 5.1 compliant
  • Supported Profiles: A2DP, AVRCP, HSP, HFP
  • Frequency Response: 5 - 21,000 Hz
  • Ear Coupling: In-ear, closed acoustics
  • Charging Time: 1.5 h for full charge / 10 min for 1 h playtime
  • Power Supply: 5 V, 600 mA max USB charging via USB-C socket at charging case
  • Battery Specification: Built-in Lithium-Ion rechargeable batteries
  • Codecs: SBC, AAC, aptX™
  • Battery Time: Up to 7 hrs music playtime with earbuds Up to 20 hrs music playtime with charging case
  • App Support: Sennheiser Smart Control App for iOS™ and Android™
  • Speaker Type: Sennheiser 7mm dynamic driver


  • CX 400BT True Wireless Earbuds
  • Silicone ear adapter sets (XS, S, M, L)
  • Charging Case
  • USB-C Cable
  • Quick Guide & Safety Guide

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Headphone Features

Dynamic Driver Size:
Transducer Type:
Dynamic Driver
Ear Cup:
Closed Back
Black / White
Headphone Type:
  • In Ear Headphones
  • iPhone and iPod Headphones
  • Smartphone Headphones
  • Wireless Headphones


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