Wahl’s Competition Series blade sets provide an amazingly smooth, show quality cut. These blades have every characteristic a professional looks for in a USA quality manufactured blade, such as having a hexavalent chrome finish for superior rust and corrosion protection that prolongs blade life. Fine Tooth Blades give a finer finished look to the coat. These are best used on fine and soft coats, for example any fluffy breeds. The final clip will be very even looking and really smooth. Fine tooth blades are distinguished by the letter “F” after the number, for example 3F, 4F, 7F. These blades will work beautifully for dogs whose coats are regularly clipped and/or brushed, however will not work on a matted dog or breeds with a thick undercoat. A Coarse Blade is generally a blade that offers a slightly wider space between the teeth on the blade that groomers can use on coarse, thick and matted coats to help feed the coat better through the blade teeth. The #4F Extra Coarse Competition Series Blade features a 8mm cutting length. This blade set fits all Wahl, Oster & Andis Detachable Style Clippers.