Bluetooth trackers have been a handy way to keep tabs on our valuables for some time now. Attach one to a bag, or slip one into your wallet, and you can then use your iPhone to help you track them down if you mislay them.

The ‘wallet’ part of that idea has, though, worked rather better in theory than practice. Even supposed slimline trackers have so far been too bulky to slip unnoticed into a wallet, which is the problem Chipolo set out to solve with its new Card tracker, which goes on sale today …

Measuring less than 7cm long by 4cm wide, it’s significantly smaller than a credit card. But the key measurement is the thickness: at just 2.15mm thick, it’s a little less than the thickness of three credit cards. Chipolo says it’s the world’s slimmest Bluetooth tracker.

While that still sounds thick – it would be fantastic to get one of these down to the thickness of a single card – in practice it slips into a card slot quite comfortably.

I personally use a Bellroy wallet (this one). These aren’t cheap, but the selling point is that you can fit a lot of cards into a very compact unit. The idea is that while you may need to carry a number of different cards, you probably only use one or two of them on a daily basis, so there are two quick-access slots and the other cards are stacked together with a pull-tab giving access to them when needed.

The problem with this and other slim wallets is that they don’t easily accommodate anything thicker than a card. But the Chipolo actually fits really easily.

Despite its diminutive size, it still manages to include a speaker, which means that you can locate your errant wallet the easy way: by sound. Touch a button in the iPhone or Apple Watch app, and the device will bleep at you continuously until you hit the button again to stop it.

The Chipolo also uses the latest Bluetooth tracker tech, so the range is 200 feet, up from the 100 feet of previous-generation trackers. Once you go beyond this range, you can still see its last-known location on a map, which at least helps if you leave it at a friend’s place or anywhere else it can be accidentally left behind without being immediately stolen.

It does have the usual problem of small Bluetooth trackers, though: the battery is not replaceable. This means that once the battery runs out – which Chipolo says should be in not less than a year – you’re left with a dead piece of plastic that you’ll need to replace.

At $35, it would be pretty expensive if you had to place it once a year, but the company offers a renewal scheme where you get 50% off a replacement if you send back the old one for recycling. That’s still expensive compared to the cost of a button cell battery, but more palatable than paying full price each time.

As with other Bluetooth tracker companies like Tile – which recently announced a new model – the company claims that the short-range nature of the tracking is offset by crowdsourcing. When you mark your wallet as lost, everyone who has the app installed will effectively join your search, and you’ll be notified if anyone’s phone gets pinged.

This is, however, more theoretical than practical. The company wasn’t able to tell me how many users it has, and even with the most popular brands, the chances of locating an item this way are pretty low.

It does, though, occur to me that this is something Apple could build into iOS. If all Bluetooth trackers were to use a common platform – TrackKit, perhaps – then every iPhone could be recruited into service to help find lost items.

In use, I found the range lived up to the 200 foot claim, and even indoors, where walls will reduce the range, the app on my phone at the back of the house downstairs was able to ping my wallet at the front of the house upstairs. The speaker sound is also impressive for its size, easily heard several rooms away.

Chipolo offers the usual reverse-find functionality. If it’s your phone you can’t find, you can press a button on the tracker to ping your iPhone, even if it’s on silent. You can also display a message on the Lock screen in case someone finds it.

Conclusions

There are a great many Bluetooth trackers out there, with prices starting at less than ten bucks. The increased range of the latest generation is, I would say, a worthwhile benefit. And if it’s a wallet you’re looking to protect, the slim fit means I don’t think you can currently do better than this one. Whether the slim form factor justifies the $35 price tag, with half price replacement each year thereafter, is something only you can decide.

The Chipolo Card costs $35. It joins the company’s existing trackers, the Classic and Plus keyring trackers which attach to a keyring or bag. It should be available for sale later today.