... 4,hardness second to diamond Ceramic Knife – High Density ZirconiaModel: 3", 4", 5.5", 6.5", ceramic knife eriesBlade Material: zirconium dioxide (ZrO2; ... ABS+TPR handleSize Available: 3", 4", 5.5", 6.5"Features: Our ceramic knives are made of ZrO2, the hardness would close to the ... have any enquiries about our product or your shipping status of your orders, please feel free to contact us through ...