This is a plastic edge cover/guard that protects the blade of the knife.
It is easier to carry than a regular wooden sheath, and is lighter and less bulky. Also, the inside is lined with suede-like cushioning material.
It is covered with a non-slip surface, so there is no need for pins and it will not scratch your knives.
*Compatible with 15cm petty knife, 18cm Gyuto and 24cm Gyuto