The Wusthof easy edge electric premium belt-driven knife sharpener (sold separately) is made for home use and designed for knives sharpened using Precision Edge Technology (PEtec). This upgrade kit includes coarse (120ZA), medium (120), fine (X30 AO) and ultra-fine (X4 AO) abrasive belts, which boasts an intelligent timing system to ensure optimal sharpening.