The Derby Extra blades have a fantastic construction with chromium-ceramic and platinum-tungsten coatings within the metal and polymer coated edges. This basically means you can enjoy a smooth shave but they will last for multiple days without dulling.
This is a full refill kit and inside the box you get 20x packs of 5 razors totalling 100 blades. The blades are precision-engineered to be strong and long-lasting.