K4 Duo AIO Audio Head Strap with Battery
- All-in-One Audio Head Strap with Built-in Battery
- Premium Sound. Total Immersion.
- 45W DualFast Charging
- Ergonomic Design for Perfect Balance & Comfort
- Built to Last. Safe for Everyday Use.
Fast, Free Shipping
Fast, Free Shipping
Enjoy free shipping on all orders over $20. Experience fast processing & reliable delivery, with your order arriving in just 3–7 business days across the U.S.
※For more details, please see our shipping policy.
30-Day Money-Back Guarantee
30-Day Money-Back Guarantee
Shop with confidence and enjoy our 30-day money-back guarantee. Simply return your undamaged products within 30 days for a full refund—no questions asked. Once your item reaches our KIWI warehouse, we’ll quickly process your refund.
※For more details, please see our refund policy.
Hassle-Free Warranty
Hassle-Free Warranty
Enjoy peace of mind with our 18 month warranty. If anything goes wrong, we’ll make it right—whether it’s a quick repair or a full replacement, you’re always covered.
※For full details, please refer to the warranty card or our warranty policy.
Lifetime Customer Support
Lifetime Customer Support
Count on us for the long run. Enjoy lifetime customer support from our expert team—ready to help whenever you need it.
※Reach out via email or live chat—we’re always here for you.
Pay with Ease
Trusted Delivery
Fits like it’s made for you.
An ergonomic design meets memory foam comfort—for a fit that feels natural, session after session.
Keeps your focus.
Gently supports the headset from above—so the view stays steady, and pressure fades away.
Built-in simplicity.
One cable. Zero distraction.
Turn. Fit. Share.
A simple twist adjusts the fit—so it’s always ready, whether it’s for you, your kid, or your co-op partner.
Now for the real headliner.
The built-in audio system isn’t just along for the ride—it’s here to transform how VR sounds, feels, and flows.
Silent control. Instant switch.
With a single flick, move your audio wherever it needs to be—Quest 3, K4 Duo, or back again.
Folds down. Stays out of the way.
The earphones rotate down with ease, and tuck away just as neatly.
Shifts with you.
The arms tilt vertically to match your natural posture—no pressure, just perfect alignment.
Dialed in to the last detail.
A final adjustment brings the earphones exactly where they should be—for fit that disappears.
Tech Specs
Meta Quest 3 / Quest 3S
459 g
250 × 280 × 135 mm
20.4 Wh
45W
*For optimal charging speed, use a 45W USB-C power adapter.
Approx. 2.5 hours (when charging with Quest 3/3S together)
+2 to 2.5 hours*
*Actual time may vary by usage
Let’s Answer Your Questions
Is this head strap better than the original one on the Quest 3/3S?
The original strap is lightweight and great for casual use, but the K4 Duo takes comfort and performance to the next level. It adds up to 2-2.5 extra hours of battery life, fast-charges both the headset and strap, and offers better weight balance with zero facial pressure. If you play for long sessions, it’s a solid upgrade.
Will the extra head strap feel heavy?
Not at all. It’s built with industry-leading weight control and a balanced design that actually feels more comfortable than the original strap — even during long sessions.
Is the battery safe?
Yes, absolutely. We use high-grade lithium batteries that pass strict safety tests from the start. Plus, the product comes with an 18–24 month warranty or replacement policy, depending on your region.
Where can I find the user guide and warranty manual for the K4 Duo head strap?
You can download both the User Manual and Warranty Guide from our official support page. Just scroll to the “Battery Strap for Quest 3/3S (KW-QA05B-SPF)” section to find the PDF files.
Customer Reviews
Hi,
I already sent. an email to your customer relations. The strap is great, as always with Kiwi products. The sound quality is really good also. The only drawback is the foam arouund the headphones. Not great for hygiene, but above all it's too fragile! We need sturdier element, and in the meantime we want replacements for foams!
Thank you
The best VR headphones I've used since the Rift CV1 in 2016. Great sound quality; the treble is clear and the bass is good but not too overpowering, it's especially noticeable with explosions and music with heavy bass, however in quieter scenes it's not very noticeable unless I turn the volume up. Bass is more prominent above 60% volume.
Also comes with a 5300mAh dual-boost capable battery (simultaneous charging with their 45w charger) which fully charges both the Quest3 and K4 battery in about 2.5hrs (40w total). The K4 Elite strap itself is also more compact and easier to adjust. Full review on my channel.
Here is my full review: https://youtu.be/3vEdDSZL7RA
Pros: Extra battery, simultaneous charging, improved audio and immersion levels, improved comfort, easy to assemble, only one small cord on the whole head strap, weight (it isn't too heavy even with the headphones on the side).
Cons: Price. This one isn't cheap!
Would I recommend? If you have the money and want a comfortable experience that includes better audio and battery included all in my head strap, then this is for you. I love watching movies with this as the audio quality is great and the immersion level is even better.
