Perfect for emergencies - the Tibloc from Petzl! Weighing only 35 grams, this ascender is extremely lightweight, so there's really no excuse not to take it on your next high-altitude mountaineering adventure. The Tibloc is so easy to use, making it perfect for emergency situations. The plastic bit has a spring and automatically press the carabiner against the rope to stop the rope, whilst the teeth securely grip the rope. There is also a marking on the ascender helping you to insert the rope properly. Perfect as a back-up for hauling, self-rescue or crevasse rescues - the Petzl Tibloc!