A hand-crank LED torch with a fold-away crank handle and a clip. Two 10-lumen LEDs. 1.75 in. x 1.25 in. (4.5 x 3.2 cm).

One minute of cranking gives up to seven minutes of continuous light. Coghlan's own figure, and it is the only number that matters here.

No batteries and no bulbs to replace, which makes this a fundamentally different object from every other torch you own. A torch with batteries in a glovebox is dead in two years whether you used it or not. This one works in ten years because there is nothing in it to go flat.

That is the use case: the emergency light that is still an emergency light when you need it. Glovebox, boat, bug-out bag, the kitchen drawer for power cuts.

Ten lumens per LED is not much — this is enough to change a tyre, read a map or find a fuse box, not to light a campsite. Buy the Tent Light for that. Buy this one because it will never let you down.

It is small enough to clip to a keyring, which is where it is most likely to actually be when something goes wrong.