Concave washer used to retain the brake shoes, sold individually.

To fit:
T2 Bay 1968-1979 Rear, 2 required per side.
T25 1980-1992 Rear, 2 required per side.
T4 1991-1996 Rear with 270x65mm drums
924 1976-1985 Rear, 2 required per side
356 1950-1965 Front and rear