Small Maillon Rapide.
When it comes to your safety, you should not do without the Petzl Maillon Rapide N° 5 in your equipment. This oval steel locking ring is tightened with a wrench. The Maillon Rapide, also known as Mayo, serves as a replacement for a carabiners when climbing. If you are climbing and then have no other option but to abseil down (e.g. due to the route being too difficult, unexpected weather changes, etc.), you often have to use a carabiners or, as a cheaper alternative, a maillon rapide and leave it behind. This item is indispensable, especially for pitons with eye plates.