The Mustad Thor Monofilament Lines are made from top grade copolymer nylon and with its unique combination of proprietary materials, they are able to provide maximum strength and also maintain its pliability. The copolymer nylon formula offers added toughness and excellent abrasion resistance. The Mustad Thor is designed to be a true all around high performance line. It is smooth and exceptional good for casting with less twisting. Superior strength and toughness with easy casting!