A stone wall alignment tool for checking the plumbness of a stone wall during construction thereof. The cooling door includes one or more heat exchangers. The first output shaft can be directly coupled with the first input shaft via a first magneto-rheological clutch, and the second output shaft can be directly coupled with the second input shaft via a second magneto-rheological clutch. The control rod is made of a material having a coefficient of thermal expansion that is significantly different than that of other filter components. The outer ground tube and the middle articulation tube present mating angled faces sloped in opposing directions.