Kiwi Design K4 Boost

Written by John Yan on 10/24/2024 for QW3  

Kiwi Design’s got a few headstraps that they produce and we’ve got two of them in recently. Today, we’re going to check out the K4 Boost for the Quest 3 and Quest 3S.

The K4 Boost is an Elite strap like design with the addition of a battery and a hinge. The package is pretty simple as it contains the strap itself and the rear support that you snap into place. A center head strap completes the setup.

I really like the thickness and feel of the rear support. When attached, there’s no movement so it stays in place on the strap. Extending from the top of it is the center strap that goes over your head and loops through the Quest 3’s center strap attachment ring as well. The padding underneath the center strap is nice and plush as well. Anything that touches your head on the K4 Boost has soft, plush padding to make it as comfortable as possible.

On the back, there’s a nice dial that you turn to extend or contract the headstrap. Rotating it right, you’ll hear a quiet ratcheting sound and the side strips slide into the back making the strap smaller. Rotating it left will extend the straps back out and it’s completely silent when you do it. It takes little effort to adjust the size so you can easily change it to fit your head.

Also housed here is the external battery that will extend the playtime of your Quest 3. Kiwi Designs says you can get up to an extra 3 hours of play, which can more than double your time. From my testing, I got about another 2 hours or so of operation, which is pretty good. On the bottom of the battery area is a USB-C connector. What’s nice is if you plug in a 45W power brick, it’ll recharge the K4 Boost battery and your Quest 3 at the same time. There’s four white LEDs on the top by the dial that shows you how much power is in the K4 Boost’s battery. They stay on when you have the K4 Boost plugged into the Quest 3 so you’ll always know how much battery power is left. I think I’d have preferred a button that turned on the lights and the lights turned off after a certain amount of time. In all honesty, it probably doesn’t take that much power to keep those lights on, but I really would have preferred a button to enable the battery level lights.

The battery is built into the strap, so you can’t change it out or replace it easily. I do like the streamlined design, but I can also see the advantage of having an easily interchangeable battery. Should the battery be depleted, you’ll have to wait until it’s charged a little to use again and should the battery become degraded, you’re now stuck with a less than optimal battery on the strap. I also tested having the strap plugged in the battery depleted and the Quest 3 battery at about 80% charged to see if there was any power leak back to the K4 Boost. I’m happy to report the Quest 3 held onto its charge and there’s no reverse charge back to the strap’s battery so you don’t have to worry about keeping the K4 Boost plugged into the Quest 3.

The back of the strap is smooth so you can lay your head down without any issues. I saw that past versions had the dial on the outside, which can be accidentally turned when lying down. With the design of the K4 Boost, this is now impossible so go ahead and lay your head down if you want to and not have the strap adjust itself accidentally.

If you’re facing the front of the Quest 3, the right side features a USB-C connector that will funnel the power from the rear. It's got a nice, short wire so it won’t hang far from the side of the face and won’t get in the way. Compared to the H4 Boost where the wire can’t be routed inside the arms and has a long wire on the left side, the wire on the K4 Boost is a lot less pronounced and sits nicely flushed with the strap’s arm.

Each arm seems pretty well built. I did some twisting and turning and they seem to hold their shape well. Time will tell if they last though, but on the initial look at it and usage for the past few weeks, they seem solid. The hinges on each arm makes it nice and easy to flip the Quest 3 up if you want to take a quick peak. Yes, you can use the pass-through cameras, but the hinges do give you the option to physically move the Quest 3 out of the way quickly and easily.

Comfort wise, I did find I felt more pressure at the top of the HMD than the area under my eyes. I’m using the Meta Quest silicon facial interface so it’s not the most comfortable facial interface out there. The extra pressure at the top did make it uncomfortable after about 30 minutes or so. But, a more comfortable facial interface might alleviate this for people like me. I do prefer a halo design like the PSVR and I’ll be looking at that one next. But, if you’re not one to be bothered by the Elite strap like design, this one should be fine for you.

Coming in at $70, it’s priced significantly less than Meta’s solution and in some instances, better designed as well. The ability to double your play time in a compact package should appeal to some. If you’re one of those that really enjoys the Elite strap design, this is also a solid pickup. As for me, I’ll be back with one from Kiwi Design that’s more my liking, but the Kiwi Design K4 Boost is a nice third party solution for extended play and a better fit for those who want this design.