... ,never discolor; 4.Heat proof,Hygiene; 5.Abrasion resistance Ceramic Knife – High Density ZirconiaItem No.: JH3A1-P02,JH4A1-P02,JH5A1-P02 ... ,JH6A1-P02Model: 3", 4", 5", 6", 7" ceramic knife A seriesBlade Material: zirconium dioxide (ZrO2; also known as zirconia ... which ensures a longer lasting cutting than other traditional steel knife.Hygiene: no smell or oxidation on the blades will transfer ...