Sennheiser CX400 II Precision In-Ear only Headphones – Black UK

Sound

Precision bass & crisp highs

Sennheiser’s dynamic driver delivers powerful low-end with accurate detail across the range — deep electronic bass lands with weight, acoustic recordings keep their natural tone. The sealed in-ear fit does half the work: with outside noise blocked, you hear detail at lower, safer volumes.

Control

Inline mic & single-button remote

Take calls and control playback without reaching for the phone. The single-button remote keeps it universal — play, pause, answer, hang up — across Android and other 3.5mm devices, with a clean inline microphone for commutes and quick calls.

Fit

Ergonomic noise isolation

The ergonomic in-ear shape creates a natural passive seal that shuts out bus engines, office chatter and aircraft drone. Three silicone ear tip sizes (S/M/L) are included to dial in the seal, plus a carry pouch that keeps the cable untangled in a pocket or bag.

Right choice if you…

✔ Want noise isolation for commuting, flights or open offices
✔ Need an inline mic and remote for calls on the move
✔ Value Sennheiser tuning over fashion-brand sound
✔ Are replacing a loved pair of CX-series earphones
✔ Want audiophile clarity under £15

Consider something else if…

✖ You dislike in-ear seals — the open-fit Sennheiser MX 375 rests in the outer ear
✖ You want a music-only pair without remote — see the Sennheiser CX300 II
✖ You need sport-secure fit for training — see the Bose SoundSport Wired

Sennheiser CX400 II — Technical Specifications

In the Box

Frequently Asked Questions

Does the inline remote work with iPhones and Android?

The single-button control (play/pause/answer) follows the universal 3.5mm standard, so it works on Android, laptops and most devices with a headphone jack. On phones without a jack, use the maker’s 3.5mm adapter — remote support then depends on the adapter.

How good is the noise isolation really?

It is passive isolation from the sealed fit — no electronics, no hiss. With the right tip size it meaningfully quiets buses, trains and office noise; it will not erase low rumble the way powered ANC does, but it also never needs charging.

What is the difference between the CX400 II and CX300 II?

Both share Sennheiser’s precision in-ear platform; the CX400 II adds the inline remote and microphone. If you never take calls on earphones, the CX300 II does the listening job for less.

Why is a discontinued model still sold new?

Sennheiser ended CX-series production, but sealed retail stock remains in the supply chain. We source it through the channels we have used since 2011 and sell it brand new in original packaging — while remaining stock lasts.

Condition

Brand New — Retail Packaging

Warranty

12-Month Maibo Warranty

Delivery

4–5 Working Days · Fully Tracked

Also Available at maibo