A ladder jack is a relatively simple triangular device which consists of brackets that are designed to attach to the rungs of a ladder and extend about a foot out beyond the rungs. When two jacks are attached to parallel ladders, a foundation is created that can support a platform, scaffolding or plank. This ladder jack system is useful for jobs that might take extended periods of time to complete, or that may be in hard to reach areas that a ladder might not be able to reach safely. It should be noted that, along with the cheapness and portability of the ladder jack, it comes with its limitations – namely that it is only designed to support light loads.