Wapsi Thin Skin is a stretchable thin plastic film great for use on a variety of fly patterns. Excellent for wing cases on nymphs, backs on scuds, sow bugs, shells on crayfish, and shrimp patterns. This material can be used on flies down to size 20. Wapsi Thin Skin comes on a backing making it easy to cut. The mottled bustard colors feature a finer mottling pattern than that of the mottled oak colors.