K4 Duo AIO Audio Head Strap with Battery for Meta Quest 3 and 3S
design
I’m getting good at writing these now because once you’ve described the design of a couple of Meta Quest 3 pro straps, you’ve kind of described them all. That’s not to say there aren’t small nuances between each, but if you’ve looked at one of KIWIdesign’s straps before, the K4 Duo is going to feel very familiar. That’s not a bad thing though, there’s value in sticking with what works and the KIWIdesign K4 Duo largely ticks all the boxes as a result. We’ll touch on what sets the K4 Duo apart from the likes of the K4 Boost in a moment, but at its core it’s a high-quality feeling elite strap clone.
Rigid arms replace the elastic side straps of the stock option, wrapping around to a rear unit that houses the 20.4 Wh external battery and a tightening wheel. There’s a decently-padded, adjustable top strap, and a similarly squishy rear ring that grabs the back of your head to hold everything in place. The plastic parts are perfectly colour-matched to the Meta Quest 3 itself and carry a similar feeling and texture, while the plush components are covered in a pleasantly soft, black faux leather. Build quality is excellent across the K4 Duo, it’s what I’ve come to expect from KIWIdesign and it’s nice to see it maintained. If it wasn’t for a couple of subtle KIWIdesign logos you’d be forgiven for thinking this was an official accessory.
What sets the KIWIdesign K4 Duo apart from others however is the addition of external headphones on either side. This isn’t a new concept, the brand previously had a similar option for the Quest 2, but it’s the first time it’s been offered for Meta’s newest VR headset. Each headphone pad is attached to the rigid side arms with a ball joint that offers a decent range of movement, and the arms themselves are spring loaded with a decent amount of resistance. Each headphone has a couple of centimeters of adjustment up and down and attaches to the main headstrap on a rotating connector, which allows you to flick them up and out of the way entirely.
performance
There’s a couple of ways to break down the performance of the KIWIdesign K4 Duo—how it performs as a general elite strap for the Meta Quest 3, and then whether those external headphones improve the experience overall. For me, it’s important to keep those aspects separate given there’s a £50 price jump from the K4 Boost to the K4 Duo. If you’re paying just over 60% more for the addition of those headphones, it’s crucial to know how they hold up when separated from the idea of an upgraded strap on its own.
Installing the K4 Duo was simple, just feed the top strap through the stock facial interface and clip on the two side arms. I’d like to see a small overhang on these arms to make it slightly less terrifying to remove the K4 Duo, but most people won’t change headstraps as often as I do so it’s a minor complaint. KIWIdesign has integrated most of the cable into the arms, rather than hanging free, which is a neat solution that sees the all-in-one cable connect to the Quest 3’s side USB-C port with almost no unnecessary slack. This cable not only handles powering and charging the headset, but takes the audio feed too, so it’s a single plug-in to be ready to go.
With the usual charging port now occupied, it’s the USB-C input underneath the rear battery unit that becomes your main connection. Cleverly, as long as you pair it with a 45W charger (which you’ll need to supply yourself), the KIWIdesign K4 Duo is able to simultaneously charge both the Meta Quest 3’s internal battery and its own external one. It’s a nice quality of life feature that means you’ll double your total playtime to around five hours from a 2.5 hour charge. This extra battery capacity does lag behind some rivals in raw juice, but the dual charging capability and total charging speed are a category-leader and worthy of real praise.
You’ll find four small LED dots on the top of the rear casing to indicate the charging state of the external battery, but these only illuminate while charging and with no button in sight, there’s no way to check your levels without plugging it in or turning it on. Other options like the Maecker Battery Strap include this and it would have been a nice addition here too.
Truth be told, after using it for a couple of weeks, I’m not sure how I feel about the KIWIdesign K4 Duo’s main event—the external headphones. There’s nothing necessarily wrong with them, they sound fine and worked as they should, I just didn’t find they added a huge amount to my experience. They don’t sound wildly better than the Quest 3’s remarkably impressive internal speakers, and while their intentions are to add to my immersion, I actually found I was constantly aware of them rubbing on my ears and this pulled me out of the virtual world instead.
This had a knock-on effect on comfort. Make no mistake, the K4 Duo AIO is considerably more comfortable overall than the stock strap and even beats major brands like Razer’s disappointing effort. But those external headphones make this less comfortable for me than the K4 Boost. The good bits remain good, the rear ring comfortably grasps the back of your head, the top strap never becomes irritating and the adjustment ring makes switching between players super simple. It’s just all slightly compromised by the headphones which I never quite found the right position for that meant they didn’t feel like they weren’t sitting correctly.
summed up
Despite having a house full of KIWIdesign VR accessories, I’m not sure I’m quite the right target audience for the K4 Duo. While I can’t argue it simply takes the excellent K4 Boost and builds upon it with external headphones that perform reasonably well, I’m just not sure it delivers that needed 60% extra benefit to justify the £129 price tag.
On the other hand, if you’re focusing on games where music and sound is absolutely key, something like Beat Saber for example, I could see this providing a little boost to your overall experience. For more general or casual VR gaming however I’m not sure they do a huge amount of elevating. Instead, look to one of KIWIdesign’s other options; the K4 Boost offers the same extended playtime and simple dual-charging, the K4 Comfort delivers just about the most comfortable head strap possible for the Meta Quest 3, or even consider the H4 and its halo-style fit.
