Ever seen a carabiner that was hollow? We had to put these on the Slacksnap to see the inside. Made by Salewa in late 70s West Germany these carabiners are rated in Kiloponds. 2000 KP = 2000 KGF = 19.61 kN. Slacksnap broke them at 19.49 kN and and 20.68 kN. At least 20 kN is included with every climbing carabiner you buy at https://hownot2.com/collections/carabiners