Aventik Wool fly fishing strike indicators are made of Wool and O-ring. The total product is close to water density. With application float-ant will secure perfect performance. Natural buoyancy: Wool has air pockets within its fibers that provide natural buoyancy, making it float better than other materials used for strike indicators. Light like a feather, great nature presentation no effect on your casting, no spooking fish. Excellent Design: Aventik fly fishing indicator come in 3 bright fluorescent colors (yellow red and orange), as well as 3 other colors (olive green brown and white) in 6 sizes, totaling 12 pieces in one pack. They are designed to be re-sizable with easy, no knot needed, and no damage on the line. Buoyancy and visibility: Wool yarn is a popular material for making strike indicators because of its buoyancy and high visibility. Different colors can be used to create a highly visible indicator that can be easily spotted on the water's surface. Lightweight and sensitive: Wool strike indicators fly fishingare lightweight, making them great for natural presentations without spooking fish. With the help of a floatant, they have excellent floatability and are ultra-sensitive to strikes, connecting you with more fish.