Sharpening Guide 'Slider'The WSTHOF Sharpening Guide is used to help glide your knife along a WSTHOF whetstone and ensures the proper angle is used while sharpening the knife. The soft silicone surface prevents the knife from scratches and helps to keep a secure grip on the guide while sliding along the whetstone. The angled guide makes using a whetstone effortless and allows for easy knife maintenance.