The Rocher Mixte by Petzl is a knifeblade piton for narrow, parallel cracks in the rock. Made of a softer type of steel, this piton adapts to the course of a crack more easily. Especially when it comes to limestone, climbers often go for soft steel hooks. However, theres a catch: in general, soft steel hooks are harder to remove from the rock and cant be used as often as hard steel hooks. The Rocher Mixte is a type P piton, which means that the UIAA has only approved it for progression on technical climbs.