This wedge shaped slider fits just underneath the back edge of your knife to keep it at a perfect, consistent angle from tip to end while sharpening the blade on a whetstone. The silicone surface prevents scratches while the underside has a layer of teflon for smooth movement. Wedge-shaped slider with structured silicone surface. The soft silicone surface prevents the blade from getting scratched. The underneath of the slider has a layer of Teflon to ensure it glides smoothly over the whetstone. The ergonomic shape of this practical sharpening aid fits nicely in the hand. The pre-set 14° angle ensures that the knife always maintains a consistent angle – from the tip to the end of the blade. Easy to use. Particularly suitable for wider blades.