2 inches

Bread crumbs or breadcrumbs consist of crumbled bread of various dryness, sometimes with seasonings added, used for breading or crumbing foods, topping casseroles, stuffing poultry, thickening stews, adding inexpensive bulk to soups and similar foods, and making a crisp and crunchy covering for fried foods. The Japanese variety of bread crumbs is called panko.
Panko is a type of flaky bread crumbs used in Japanese cuisine as a crunchy coating for fried foods,
Panko is made from bread baked by electrical current, which yields a bread without a crust, and then grinding the bread to create fine slivers of crumb. It has a crisper, airier texture than most types of breading found in Western cuisine and maintains its texture baked or deep fried, resulting in a lighter coating.