For choppy fast-water streams and rivers or times when you are catching lots of trout and want a fly that will float no matter if it is wet or covered in trout slime, the Irresistable Wulff is the perfect pattern. It could be a mayfly, caddis fly or a terrestrial but most importantly it will stay on top of the surface where it belongs due to its clipped deer hair body and its heavy hackle section. Like all Wulff patterns, its white calf hair wing is easy to keep on eye on at all times. Per 3. Sizes: 10, 12, 14, 16. Cancer and Reproductive Harm- www.P65Warnings.ca.gov. Type: Flies.