The Sieger Long Life sharpener made of synthetic ruby is 20 times harder than hardened steel. The most unusual thing about this sharpener is the high efficiency: Less time for sharpening in combination with an extraordinary fine edge leading to high edge retention. In addition, the sharpener is more durable than a diamond sharpener, for example, because it is not a coating but a solid material. The Knife Sharpener can be used dry or wet. After use, simply clean with a sponge. Sharpening tube length 20 cm.