The use of these drills boards has help many climbers start to develop a better understanding of climbing on steep rock. Although you can develop one for the rock over it is the tricky techniques of the drop knee, inner flag and outer flag that this drill boards really helps.
For most climbers the first time they use a drill board they struggle with the pattern of movement. In that they can often get the beginning or the end position but it is the transition from one to the other that become the problem.
It is this ability for a climber to repeat many different combinations and permutations of the movements need in order to get the underlying fundamental principles dialled in.
As such whilst know what a drop knee, inner and outer flag are is great this exercise really helps you get to grips with the body positions needs to make the transitions smooth and effective.