The steel blades lightly brush against one another – sharpening themselves as they work. This results in blades that are sharp as day 1 after 3 years of use. This all-in-one trimmer conveniently trims and styles your facial hair and clips your hair. Use the trimmer without a comb to get clean, sharp lines around your beard, neck and hairline. The trimmer's shelf-sharpening blades remain as sharp as day 1, even after 3 years of use.