The FST tool straightens commonplace 8, 10, 12, or 14 fins per inch. The tool features one-piece adjustable combs. The resilient nylon comb material will not damage the soft aluminum fins of condenser or evaporator units. Malco fin tools function by either pushing or pulling and efficiently straighten fins in tight quarters or where multiple passes over bent fins are required. Comfortable offset handles provide a sure grip and protect knuckles from scraping.