NOGENT Trois Etoiles Expert range of chefs’ knives, the only cook's knives which never need sharpening! The secret is in the serrrations. With 4 serrations per mm, the teeth are practically invisible to the naked eye. It is this technology that means they never have to be sharpened as they never wear down. The knives are incredibly sharp, very comfortable to use, you don’t feel the serration when cutting, and the knife really cuts, and doesn’t tear the food.