I've been seeing a lot of these ads recently, probably because I clicked on one of them a few months back. The headlines accompanying the ads have become increasingly incredible. Taking on an $11.2 Trillion market? Quite impressive when the entire US GDP is less than twice that at $18.5 Trillion. Clicking through takes us to an article at decentric.org, which says: To cut to the chase, these devices (which are actually far larger than the unrelated stock photo used in the ad) are NOT replacing GPS. In fact they rely on GPS to actually work in a useful manner. But what are these miracle devices? What's that thing on the finger supposed to be? The Decentric article describes it as a "bridge component", which is one of four components that XYO says makes up their system. Impressive sounding? But what is it talking about? What's a "heuristic witnesses?" Google the term and you'll find that only XYO have ever used this term before. What's a "heuristic" then? "Heuristic" is a term for an ad-hoc rule or procedure - basically something that you made up that seems to work well. In the XYO context they are using it in the way it's sometimes used in blockchain and cryptocurrency technology, which is an algorithm for doing something with multiple pieces of data. But instead of referring to the algorithm as a heuristic, they refer to the pack of data that results from that algorithm. With that in mind, let's try translating XYO's description of "Sentinel components" Sentinel components are heuristic witnesses. They observe heuristics and vouch for the certainty and accuracy of the heuristic by producing temporal ledgers. The most important aspect of a Sentinel is that it produces ledgers that Diviners can be certain came from the same source by adding Proof of Origin to them. Translation: Sentinel components record their location and their location based interactions with other sentinals. They digitally sign their GPS or bluetooth derived location records with a device-unique key, they including the time stamp, and call that a "heuristic". They record these heuristics in order in a "ledger" and send it to the servers ("Archivists") via a "bridge". The small yellow device there is an XY4+ Key Finder, a bluetooth device that connects to your phone. It does not record anything itself, just connects to your phone and the phones records the location (of the phone), so it can track when the Key Finder was last within range of the phone. It can also make the device beep if within range. The Grey medium sized sentinel is an XYGPS This uses GPS to determine its location, and then sends that location back to you via a the cellular network and the internet. As it's essentially a small cell phone its main problem is a short battery life of just a few days, compared to the bluetooth tracking device, which can last over a year. Inside it looks like this: XY describe the largest (teal colored) sentinel as a "Super location miner", which I'm guessing has a bigger battery and more peer-to-peer connectivity (so it can record the locations of other nearby sentinels) So the basic claim that "THIS TINY DEVICE COULD REPLACE GPS AND SAVE US $2 MILLION PER DAY" is obviously false. The XYO network relies on the GPS network. It does add another layer on top of that, recording locations, and recording when one device is near another device. But location reporting with any accuracy still needs GPS. You could not, for example, replace the GPS in your car with something that was not GPS (or an equivalent satellite triangulation service, like the Russian GLOSNASS). Unfortunately one of the XYO co-founders seems to imply that your could in this video, saying it could be used in self driving cars (although he may mean in addition to GPS, to provide additional trust, but it's not clear how that would work). But what's that device on the finger? It's nothing directly to do with XYO or GPS, in fact it's a stock photo: https://www.dreamstime.com/modern-e...component-rf-transformer-human-image111096974 The device show on the finger is a transmission line transformer, used in wired network connections, not wireless. So if that's not a bridge component, then what it? A bridge here just connects the sentinel devices (like the key tracker) to the internet. So your phone could be one (it could also be a sentinel). A clue is the icon the XYO use: That's the Raspberry Pi logo. These are just small general purpose computers. You can add a Bluetooth adapter and then stick it in a location you think a bridge might be needed. It's small, but quite a bit larger than the stock photo suggests.