A folding reflective triangle that warns other road users of unusual or dangerous conditions, such as a crashed or non-starting vehicle.

Folded, the triangle is easily stored in a door, under a seat, or somewhere else in easy reach.

A warning triangle in use on the road.

To use, just unfold the triangle and extend the legs, then place at least 100 meters from the hazard, so that other road users have time to react to the warning before reaching the hazard. In some cases, visibility might be too low for such a long warning, in which case, just place it as far as possible from the hazard.