Smith's SMDRET diamond retractable sharpener offered, in a multiple layers of medium diamond 400 grit and monocrystalline diamonds makes sharpening quick and easy, while still giving that razor sharp edge on your knives, tools, or hooks. The rod is reversible and can be adjusted to variable lengths. This diamond retractable sharpener features an unbreakable, diamond coated steel rod, which is specially designed to sharpen all types of knives, including serrated. Smith's SMDRET diamond retractable sharpener is light, compact, and durable and aluminum housing protects the sharpening rod. This diamond retractable sharpener has a sharpening groove for hooks and a shirt pocket slip for easy storage.