Made of zirconia, high density; Hardness and abrasion resistance is 60 times than metal knife; It needn't to grind for ever if it doesn't drop to ground, suffer external force or used to chop; Suitable for cutting frozen meat; vegetables, fruit, fish and seafood, etc. (not including food with seashell); Great for cutting food that can eat directly; Lead-free, toxic-free, acid-resistant and alkaline resistant, never get rust