Leaders and tippets are typically made from materials such as nylon and fluorocarbon. Nylon leaders are flexible, durable, and affordable, making them a popular choice for most fly fishing situations. Fluorocarbon leaders, on the other hand, have the advantage of being nearly invisible underwater, making them ideal for situations where fish are easily spooked. Both materials have their own characteristics and strengths, so it's important to consider your fishing conditions and target species when selecting the appropriate material.