Fin Comb - Two Sizes - #18 and 20 Fins per inch. One size on each end. Measures approximately 4 3/8" x 3/4". These are the most popular sizes of fins per inch used on AC condenser and evaporator coils. Works better than most styles. Can be used on other coils such as window units, PTAC's, mini splits, radiators, ect.  New and made by Supco. Good quality.