The Global brand of Japanese knife sharpeners are made in the same Yoshikin factory that also manufacture Global Knives. Global uses the finest quality of Japanese grit to produce top quality whetstones and pull through sharpeners which are designed to sharpen any brand of knife. Global sharpeners are all designed to be used with water. Wheels course grit should be used to restore very blunt or chipped knives, medium grit should be used for general sharpening and fine should be used to finish the knife to ensure that perfect edge.