Amadou fly dry patch

Amadou is a spongy material that comes from the soft, stretchable interior layer of the Fomes fomentarius mushroom, also known as the "tinder fungus" or "horse's hoof fungus". The mushroom is large, amorphous, and inconspicuous, and grows on tree trunks in Eurasia and North America. Its outside is hard and bark-like, but its inside is soft and leather-like. It is a great material for absorbing water from your flies to make them dry and float again. 

measures 2.5" square