The Green Rubber Leg Copper John popular and effective pattern has taken the fly fishing world by storm. This fly sinks quickly and can be used as a deep nymph or a dropper. Fish seem unable to resist the combination of color, flash, and realistic shape. The addition of rubber legs creates an added attractant that makes this fly hugely successful. Most guides and serious anglers never enter the river without several sizes, colors, and variations of this rubber leg pattern in the fly box.