This is a Diamond Retractable Sharpener featuring an unbreakable, diamond coated steel rod, which is specially designed to sharpen all types of knives, including serrated. Multiple layers of medium grit, monocrystallin diamonds makes sharpening quick and easy, while still giving you that razor sharp edge on your knives, tools, or hooks. The rod is reversible and can be adjusted to variable lengths. It has a sharpening groove for hooks and a shirt pocket clip for easy storage. The unit is light, compact, and durable.