InstruMMents 01 review: An intriguing device for making fine measurements, but prone to human error

Price when reviewed

The InstruMMents 01 is an innovative measuring device. It looks like a pen, and you use it by simply rolling the end along whatever you want to measure.

It’s a fascinating idea, and after launching on Indiegogo last year, the InstruMMents 01 ended up raising nearly four times its original funding goal. It can now be found on InstruMMents’ website for $185 (around £150) including shipping and taxes: you can choose from three models, with either an integrated pencil, ballpoint pen or stylus. Alternatively, for £50 less, you can opt for the more portable 01Go device, which is designed to be attached to a key chain.

InstruMMents 01 review: Technology and mobile app

The InstruMMents 01 is described by its manufacturer as a “dimensioning instrument”. A roller at the end of the barrel works in combination with a tracking laser to measure distances to within a claimed 0.1mm error margin.

Measurements are relayed through Bluetooth to your Android or iOS device; to receive them you’ll need to download the free InstruMMents Lite app on the Play Store or on the App Store. There’s also a Pro app coming in the next few months: for a $10-per-month subscription, this will let you measure 3D curves as well as straight lines – potentially a game-changer for digital designers who want to create virtual models of real-world objects.


Pairing the device with your phone is extremely simple: just tap and hold the top of the pen for three seconds and wait for your smartphone to confirm that it’s paired. Of course, if you don’t have a smartphone with you, or don’t have enough battery power, the InstruMMents 01 is a paperweight.

The app is easy to get your head around. At the top right you’ll see the option to choose from a wide range of metric and imperial units, stretching from millimetres to miles. I’m not sure how you’d measure a mile with this device, but it’s nice to have options.


Once you start taking measurements, these appear on the app’s main screen. You can label each number, for your own reference, with a descriptor such as “width” or “length”. Alongside the default options, you can customise these labels to suit your needs.

InstruMMents 01 review: Design and build quality

The 01’s silver and black design is easy on the eye, and it’s beautifully crafted out of aluminium and steel, so it feels like a premium device. If you want to use it as a pen or pencil, you may find the top-heavy design feels a bit awkward for longer writing sessions, but it’s fine for making quick notes or jotting down measurements.


One caveat is that the internal batteries aren’t rechargeable, and they’re of a proprietary design. You’ll pay £20 for three spare batteries, each of which is rated for up to six months of use. It’s a frustrating long-term running cost, and it means you’ll be left high and dry if, for whatever reason, the manufacturer stops making them.

You can also buy replacements for the pencil lead, ballpoint pen, stylus tips, and rollers on the company’s website. A single replacement roller is included with every InstruMMents 01.

InstruMMents 01 review: Performance

The key requirement of a measuring device is accuracy, and when I used it with care, I found the InstruMMents 01 to be perfectly accurate. However, if I rushed at all, I found it far too easy to accidentally over-rotate the roller. To get good results, I had to take care to place the device perfectly vertically onto the surfaces to be measured, and to do the same when lifting it off.


If you want to use the 01 for measuring items of moderate size, another problem is the difficulty of rolling in a straight line. Without a perfectly steady hand, and a perfectly flat surface, the 01 picks up every wobble and bump, which throws off your results. If you can use a ruler, a tape measure or a range finder, you’ll probably get much more consistent, albeit less precise, results.

Of course, those tools can’t match the 01’s claims of accurately measuring 3D curves. But since the Pro app isn’t yet available, it remains to be seen how credible those claims are. If you buy the device now, you’re taking something of a leap of faith.

InstruMMents 01 review: Verdict

For a designer working with modestly sized objects, the 01 could be an extremely useful measuring device. For many jobs, though, you’ll do just as well with the Bosch digital laser measure, or a sub-£50 range finder on Amazon. Or you could always make do with a ruler or tape measure.

Don’t get me wrong, the the InstruMMents 01 is a cool and promising gadget, and its 3D capabilities could be a unique selling point. But I wouldn’t spend £150 on it – certainly not before I’ve had a chance to experience its full potential.

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