- Modern equivelant Dowty washer (outer washer is zinc plated steel, inner washer is neoprene). This washer is used behind the timing chamber filter bolt and also at the back of the rear cylinder crankcase mouth bolt (that has an oil feed).
It can also be used behind 1/4 BSP fittings - but I prefer to use copper or red fibre on those applications, as they look more original