This is a crinkle-cut potato slicer (sometimes called a "mandoline" or "crinkle-cut vegetable slicer") used to cut vegetables and fruits into slices with wavy edges.
The blade is usually made of stainless steel to ensure durability and rust resistance.
It is used to make crinkle-cut French fries or decorative cucumber and carrot slices for salads.
The slicer allows for uniformly shaped and thick slices.