K2's Bottleneck is at 8350m. The Bottleneck is a narrow couloir, which is overhung by seracs from the ice field east of the summit. climbers have to traverse about 100m exposed to the seracs to pass it. This is a location known as Abruzzi Spur in the south east spur, the most used route to the top of K2 but this part is very dangerous and technical of the route.