At the airport this summer, I found myself having to use a self-service machine to check my own bags. Not being an airport employee, and also being quite epically tired, I didn’t do the greatest job of attaching the label to my suitcase.

The conveyer belt suddenly lurched into action and I was forced to watch as my imperfectly labelled bag disappeared.

I spent the rest of the time until the plane landed alternating between marvelling at my inability to stick a label onto a bag handle and wishing I’d invested in some AirTags so I’d know if my suitcase had made it to my destination with me.

So, that’s what I bought today, while they’re on sale for Prime Day.

In the UK, Apple sells AirTags for £35 each, or £119 for a four-pack. In the US, you can buy a single AirTag from Apple for $29 or a four-pack for $99.

But if you buy from Amazon UK today, you can get a single AirTag for £28 (or two for £56), which offers a comfortable 20% saving. If you can spend a bit more, you can buy a four-pack of AirTags for £84, down from £119, saving you over 29%.

On Amazon US, you’ll get a big 31% discount on every AirTag you buy: they’re down from $29 to only $19.99 each.

You’ll also get free delivery. Bear in mind that you won’t be able to get the free engraving service that Apple provides, but as AirTags are often most useful when they’re hidden, I don’t count this as a big loss.

You’ll need Prime membership to get the deal. Prime Day runs from 7-8 October inclusively, so today is the last day to get them on sale. Don’t wait too long if you want them.

AirTags are pretty much endlessly useful. Not only for peace of mind at airports, but to attach to pet collars to track adventurous dogs and cats, protect pricey handbags or wallets from theft, or attach to your keys if you often lose them.

You can use an AirTag if you have an iPhone or iPad but some older models aren’t compatible. You’ll need an iPhone SE, iPhone 6s or a newer model iPhone; an iPod touch (7th generation) with iOS 14.5 or later; or an iPad Pro, iPad (5th generation or later), iPad Air 2 or later, or iPad mini 4 or later with at least iPadOS 14.5.

See all the best Prime Day deals spotted by our editors in our Prime Day round-up.