RedLine K-9 Round Biothane Tracking Lines utilize 520 Round Biothane Beta®, a material resistant to water absorption and rot. With a robust break strength of 500 pounds, these lines are lightweight yet sturdy, ideal for tracking or nose work activities. Biothane® sets the benchmark for all-weather lines, ensuring reliability in various conditions. Completed with a solid brass clasp, these lines are available with or without handles for added convenience.