The Washer(10x15x1.5) is the lowest priced item on this Front Brake Hose (model L E24) schematic.
With twelve applications this Washer(10x15x1.5) is the most specified part.
seven components are shown in this Gsxr1100 1989 (k) (e01 E02 E04 15 16 17 18 21 22 24 25 34 39 53) Front Brake Hose (model L E24) exploded diagram.
