Tracker glossary

A to Z

19 terms, defined

Anti-stalking alertalso: unknown tracker alert

The automatic warning your phone shows when a tracker that is not yours has been traveling with you. Apple triggers it when an AirTag or Find My accessory is separated from its owner and seen moving with you over time; Android has the same protection under Settings, Safety & emergency, Unknown tracker alerts, including a manual scan. The limit worth knowing: both systems look for Bluetooth beaconing, so neither one finds a hidden cellular tracker. Step-by-step on both platforms.

Bluetooth Low EnergyBLE

The radio standard every item tag uses. It is built to sip power — which is how a coin cell lasts a year — and that frugality is exactly why the range is short and why the tag cannot reach the internet by itself. A BLE tag does not know where it is. It shouts an identifier and waits for someone else's phone to do the knowing. How that actually works.

Bundled servicealso: prepaid service, no monthly fee

A cellular device sold with a period of service — usually twelve months — paid into the purchase price. It is legitimately not a monthly fee, and it is also not free: month thirteen has a price, and the box rarely prints it. Treat the renewal rate as part of the purchase decision, because across three years it is usually the larger half. Which devices are genuinely one-time payments.

Crowd networkalso: finding network

The mechanism behind every no-fee tag: millions of other people's phones listening for tags and relaying what they hear. Apple's is Find My, Google's is Find Hub, and Tile runs its own on the backs of other Tile users. This is why a tag costs nothing to run — the data is carried by a stranger's phone plan — and also why coverage is a function of population rather than of the tag. Find My vs Find Hub.

Geofence

A boundary drawn on a map that triggers an alert when the tracker crosses it. Useful and routinely oversold: the alert can only fire as fast as the device reports, so a geofence on a cellular tracker reporting every five minutes is a five-minute-late geofence, and a geofence on a Bluetooth tag is not really a geofence at all. On a wireless dog fence the boundary is enforced by a correction rather than a notification, which is a different product with a similar word attached.

GPSGlobal Positioning System

A receiver that works out its own position from satellites. It needs no network and no subscription to do that — but it also cannot tell anyone the answer, which is the part everybody skips. The reporting is what costs money. A device advertised as a “GPS tracker” with no monthly fee is almost never a GPS receiver; it is usually a Bluetooth tag. The difference, in full.

IP ratinge.g. IP67, IP66

Two digits: dust resistance then water resistance. IP67 means dust-tight and able to survive immersion in a meter of water for thirty minutes — Apple publishes IP67 for the AirTag and Chipolo publishes it for the LOOP. IP66 means dust-tight and able to take powerful water jets but not immersion; Pebblebee publishes IP66 for the Clip 5. Neither is a swimming rating, and none of it is a permanent property: seals age. What the ratings do and do not cover.

LTE-M and NB-IoTcellular IoT standards

Cut-down cellular standards designed for devices that send tiny amounts of data on a battery. They are the reason a cellular tracker can run for weeks rather than hours, and they are still cellular: there is a SIM, there is a carrier, and somebody is paying. Bluetooth vs cellular vs long-range radio.

OBD-IIthe diagnostic port under your dash

The standard socket every car built for the US market since 1996 carries, and the easiest place to install a vehicle tracker: the car powers it, so it never needs charging. Two trade-offs nobody mentions in the listing — it is plainly visible to anyone who looks, so it is not a covert device, and it occupies the port a mechanic needs. OBD vs hardwired vs magnetic.

Precision Findingalso: AR finding, directional finding

Walking directions to a tag over the last few meters, using ultra-wideband to measure distance and bearing rather than just signal strength. It is genuinely good and it is also the most platform-locked feature in the category: it needs a tag with a UWB chip and a phone with one. Without UWB on both ends you get a louder beep and a warmer-colder guess.

Radio direction-findingalso: RF tracking, telemetry collar

A handheld receiver talking straight to a transmitter on the collar, with no network between them. This is the only form of live tracking on this site that genuinely has no subscription and no coverage dependency — it works in cellular dead zones precisely because it never needed a cell. The cost is that the position exists only on the handheld you are carrying, so nobody at home can look it up. Where this beats a cellular collar.

Rangeas printed on the box

An open-field, line-of-sight figure, and therefore close to useless indoors: Samsung states up to 120 m for the SmartTag2, Chipolo states up to 120 m for the LOOP, Pebblebee states 500 ft for the Clip 5. Walls eat most of it. The number that decides whether you find your bag is not this one — it is how far away the nearest participating phone is, which in a city is meters and in open country is miles. Why range specs mislead.

Replaceable vs rechargeable

A CR2032 coin cell you swap once a year, or a USB-C port you remember to use. Replaceable cells mean a tag that never truly dies and a battery you can buy anywhere; rechargeable means no consumables and a device that is unavailable while it charges. Older sealed tags were neither — when the cell went, the tag went. Tags you can put a new battery in.

Reporting intervalalso: ping rate, update rate

How often a cellular tracker wakes up, fixes its position and sends it. It is the single biggest lever on battery life — the same device can last days or months depending on this one setting — and it is usually what a brand's more expensive plan tier is actually selling you. “Real-time” is a marketing word for a short interval, not for a continuous stream. Battery life compared

Separation alertalso: left-behind alert, smart alert

A notification when you walk away from your tagged item — the feature that prevents a loss instead of investigating one. It is free on some platforms and a paid tier on others, which is the single most common reason people feel misled after buying a tag. Which platforms charge for it.

SIM-free

No SIM card in the device. It means no cellular bill, and it does not mean no cost: a satellite communicator has no SIM and still needs airtime, and a Bluetooth tag has no SIM because it has no radio capable of reaching a network at all. What SIM-free really buys you.

Subscriptionalso: plan, membership, service fee

The recurring cost of the network a tracker reports over, and on a cellular device it is the purchase — the hardware is often sold near cost to get you onto it. Published examples this site cites: Tractive at $9 a month on a one-year Basic term, Spytec at $14.95 month-to-month or $12.95 paid annually, and Life360 memberships from $9.99 a month. Across thirty-six months those are $252, $466.20 and $359.64 respectively, which reorders every “best tracker” list in the category. The full three-year table.

Three-year cost of ownershiphow this site ranks things

Device price plus thirty-six months of the brand's own published plan rate. Three years rather than one because it is roughly how long people keep a tracker, and because a one-year view flatters bundled-service devices that start billing in month thirteen. It is the number every roundup here sorts by, and the reason the cheapest device is frequently the most expensive choice. How the math is done.

Ultra-widebandUWB

A short-range radio that measures distance by timing a pulse, accurate to centimeter scale where Bluetooth signal strength is accurate to “somewhere in this room”. It is what powers Precision Finding, it is present in only some tags and some phones, and it does nothing at all for long-range location.