The Litho looks like a set of miniature sci-fi brass knuckles, but it’s actually a motion controller that’s going on sale today for developers, with the goal of launching for everyone by the end of the year. Developed by a three-person team in the UK, the Litho fits around the first two fingers of your hand. It combines motion-control capabilities and haptic feedback with a small underside trackpad, so you can use it with a combination of pointing, swiping, and tapping. Now, developers just have to figure out what it’s good for.

Nat Martin, head of the Litho’s design team, says the controller was conceived with augmented reality glasses like Microsoft’s HoloLens in mind. It offers basic support for the HoloLens, but for now, it’s largely built around Apple’s mobile augmented reality platform ARKit. One demo video shows wearers placing objects in an augmented reality iOS app. Another shows people controlling smart home gadgets like thermostats without pulling out their phone.

Motion-control hardware companies can have a tough time finding their niche. Most people aren’t looking for new phone and computer interfaces. Headsets like the HoloLens and Magic Leap One — which are a more natural fit for motion controllers — are far from mainstream, and in any case, these devices already have controllers. The Litho is charting similar territory to the Thalmic Myo armband, which ceased production last year, and the Nod ring, which never realized its ambitions of becoming an all-purpose controller.

Martin thinks the Litho has a winning formula, though. The development kit, which is being made in small batches, costs $199. But he wants the final product to cost less than $100, so people might consider buying it for even occasional use. The original version of the Litho, called Scroll, was a single-finger smart ring. But making a size to fit every customer — like Nod, which offered a dozen different options — would be “a complete nightmare.” So the current model is a one-size-fits-all device meant to be worn only when you need it. The hardware anchors around two fingers, which also allows for a larger trackpad. (That said, I haven’t worn the Litho, so I can’t personally vouch for the design.)

Even if it fits, why should someone buy a Litho? Well, the site doesn’t offer any really mind-blowing options, unless you’ve got a huge number of smart gadgets. But it’s attractive as a precise, flexible mobile AR interface that doesn’t block your view, unlike a normal screen tap. There’s some precedent for this kind of accessory since Pokémon Go supports a $50 motion controller for “throwing” pokéballs. If the Litho can add similar value to enough other apps, that might make it worth buying — especially if those are specialized apps for professionals, like 3D design software.

Granted, that’s an optimistic assessment, and it depends a lot on app makers buying and using this first version. But with the device ready to ship, it’s on the verge of getting a real-world test run.