Sleep headphones typically consist of a headband with some ultra-thin drivers embedded, letting you position your head more-or-less as you normally would. You’ll find them going cheap on Amazon, but most aren’t exactly what you’d call a quality product.

The $249.99 Kokoon Nightbuds are much more interesting. They are in-ear wireless headphones with a bespoke design, clever technology and a dedicated app that lets you choose a relaxing soundscape and even use the earphones as an alarm.

I’ve used them for the past few months to find out what they are like.

Most audio-based sleep gadgets are quite gimmicky, but the Kokoon Nightbuds have some genuinely useful and well thought-out characteristics.

First, the earpieces themselves are ultra-shallow. This ensures they stay within your ear canal, meaning they won’t be pushed up into your ear cartilage as much as a standard design pair when sleeping on your side.

The Kokoon Nightbuds are neckband earphones — not a particularly trendy style these days — but the battery block is also slim, and sits behind your neck. This is important for those who sleep on their back. Both of these elements aim to get rid of the lumpiness of earphones, which is what makes a normal pair unsuitable for use while your sleep.

Kokoon’s slightly odd-looking zig-zag cable is crucial too. It lets the earphones deal with movement as you sleep, without pulling the earpieces out or leaving slack that might get snagged on, say, the corner of a pillow.

There is an issue, though. Despite the smart design the Kokoon Nightbuds just aren’t that comfortable for side sleepers who use latex or memory foam pillows. I had to take them out to get to sleep when using a latex pillow, defeating the point of the pair.

Feather or hollow fibre pillows are a much better fit. Kokoon says as much in the FAQ section of its app.

The other important part of the hardware is an optical heart rate sensor that sits inside the right earpiece. This isn’t a fitness tracker. You won’t see heart rate results in the Kokoon Nightbuds app, but this sensor does let the earphones judge when you fall asleep.

Kokoon’s concept is that you’ll play one of its relaxing soundscapes while you try to get to sleep. And when you do, the Nightbuds will either phase out or switch to playing pink, white or brown noise. This is intended to stop outside noise waking you up.

In this context, such white noise arguably makes more sense than adopting active noise cancellation. The Kokoon Nightbuds don’t have that, just the passive noise blocking supplied by the little silicone tips.

In the MyKokoon app you set your bed time and when you want to wake up, because the earphones can also attempt to wake you up by phasing in sound. How effective this proves to be is likely to vary from person to person, but the issue I had was the battery occasionally running out before dawn. The battery lasts “10+” hours according to Kokoon.

While this matches the Bose Noise-Masking Sleepbuds II, it’s fairly poor stamina for a pair with a fairly large block that holds the battery and core electronics. You’ll have to keep the Kokoon Nightbuds regularly topped-up to avoid disappointment, or being late for work.

In the pair’s favor, they are far more flexible than the Bose alternatives. You can use the Nightbuds as normal earphones. They’ll play any music you like, and I’ve spent quite a lot of time using the MyKokoon’s sound library as a way to block out distractions while working during the day.

The app offers a fistful of audio “scenes”, such as underwater, rain, one that emulates sitting around a fire in a forest, and birdsong. They can be helpful for those who suffer from tinnitis, and occupy your mind just enough to make settling down easier. White noise drones can help babies sleep, but it works for us adults too.

Kokoon’s library isn’t close to the brain.fm service I regularly use for distraction free audio and music, but the classic bases are covered.

There’s a little surprise in the kind of drivers the Kokoon Nightbuds use too: the balanced armature. Years ago these were only really found in audiophile earphones but they likely have a part in allowing this pair’s earpieces to be as small as they are.

They are also responsible for a sound characteristic some may not like, fairly lean bass. A balanced armature (BA) driver usually struggles to reproduce powerful low frequencies, which is why many pairs either use multiple BA drivers, or bolster the low-end with a conventional dynamic driver.

This means, for example, the storm soundtrack in the MyKokoon app doesn’t have quite the weight you might expect. You might also imagine that a well-paced thunder noise might wake you up as you’re nodding off, but a well-designed sleep soundscape avoids these kinds of shocks anyway.

I do think the sound would benefit from being a little fuller, in part because the upper mids and lower-treble are not entirely refined and smooth. However, like most balanced armature pairs the audio is still clear, and has good stereo imaging — handy for rendering those sleep-bringing soundscapes.

The Kokoon Nightbuds are the most complete sleep earphones around. You can use them as normal wireless headphones, unlike the Bose Noise-Masking Sleepbuds, the earpieces are ultra-slim and the app adds meaningful features that make this pair more than just funny-looking earphones.

Much like the Bose pair, though, the high cost restricts their appeal — and the standard package only grants two years of MyKokoon app use, after which you’ll likely be encouraged to buy a new pair or pay for access.

The key parts to bear in mind are that the Kokoon Nightbuds are not that comfortable for side sleepers who use latex or memory foam pillows and that the just-OK battery life demands some upkeep if you want to use the wake-up feature. You need to plug these earphones in to charge, and they lack the breezy charging of the Bose Noise-Masking Sleepbuds, which can be left in their charge case at your bedside.