Proline is known as having a very high-quality self-regulating heating cable for pipe heating trace and roof and gutter heating applications. Their PLSR cable is known as being very high-quality and they even claim that their cable does not bulge when bent in a tight radius which can be a failure point. Now they have taken this cable and used it to create a standard 50, 75 or 100 Foot Length pre-terminated kit!
Proline Pre-terminated Self-Regulating Heat Cable for Water Pipes and Roofs – 50, 75 or 100 Foot Long – 120 Volt – 6 Watts per Foot at 50 Deg. F. – Plug and Cord Cold Lead (Plug Included)
https://morelectricheating.com/products/MANUFACTURERS/PROLINE/PLSR%20KIT.aspx