When climbing routes featuring large cracks in the rock, it is possible and sometimes required to use a fist jam. A fist jam is when a climber places their hand ino the crack and makes a fist, which should allow the climber to pull on, basically using the hand as a large nut. In some cases the crack will be too large for a single fist. Cracks of this size are referred to as “Off Width”. When this is the case another hand can be added wrapped around the fist, not to mention a knee, or elbow. This technique is known simply as “jamming”.