How we check facts

Where facts come from

Prices come from each maker's store and plan pages. Battery, weight, range and coverage come from its product pages and help centre. Ownership, shutdowns and recalls link to the company's own pages or to reputable reporting.

Each fact is tied to the maker's own page that states it. The consequential claims, prices first, are checked against that page by hand and corrected where they don't hold up.

The three kinds of tracker

• Cellular GPS: GPS plus a SIM. Works wherever there's mobile signal, and almost always needs a plan.
• Radio: the collar talks to a handheld or base station. No phone network, limited range.
• Bluetooth tag: no GPS. Strangers' phones report where they heard it.

When a maker doesn't say

We write "Not stated". That's different from "No". Filters never count it as a match, the range rings list those trackers separately, and a missing renewal price is never filled in with a guess.

How costs are compared

• Prices are the maker's list prices, in the maker's own currency for the store we could check. Sale prices appear only in notes.
• "3 years, all in" is the device plus the cheapest way to pay for three years of the cheapest plan that shows location. Where the maker doesn't state a renewal price, the total says "if the price holds".
• Prices in different currencies are never ranked against each other.
• Prices change and differ by country and tax. Always check the checkout page.

What we don't do

• No scores, stars or "editor's rating". Guides explain their picks instead.
• No accuracy or battery tests of our own. Battery and range are the makers' claims, labelled as claims.
• No affiliate links or sponsored placements. Nobody pays to be listed or ordered.