Used for self-belaying on fixed ropes, as a handle when you need to pull on a rope, as well as for climbing ropes. Hand grip insulates hand in cold conditions, large enough to take a bulky glove, safety catch can be operated with one gloved hand. Ascension features a lug which helps prevent the rope from pulling the cam through the top of the ascender in the event of shock-loading.
Any mechanical ascender can severely damage or destroy the rope if overloaded or shock loaded.
It is very easy to overload these devices when used in mechanical advantage hauling systems. They should never be used to catch a load in a dynamic situation such as belay. Actual ascender strength in the field is dependent on the rope used.