MATERIALAngle guide's inside is made of plastic,to prevent it from scratching your knife.And it nicely allows you to better find the angle of the sharpening. FEATURESThis whetstone with whetstone holder can help you sharpen the knife at a perfect angle on the grinder,which saves manpower and is more convenient to use. EASY TO USEFix angle guide to the appropriate location of knife blade.Both hands hold the handle and the back of the knife,ceramic part contact the surface of whetston or diamond,make knife blade into a fixed angle, move the blade,back and forth over the sharpener by using little pressure. APPLICATIONSuitable for outdoor or kitchen,wide range of applications,practical and light and portable.