That's heat shrink tubing, but we're talking about one of these: [1]: https://www.holley.com/products/engine/engine_dress_up/hoses_and_coverings/parts/573-109

That's heat shrink tubing, but we're talking about one of these: [1]: https://www.holley.com/products/engine/engine_dress_up/hoses_and_coverings/parts/573-109 https://www.holley.com/products/engine/engine_dress_up/hoses... [2]: https://www.oreillyauto.com/detail/c/dorman-conduct-tite/lighting---electrical/connectors---terminals/wire-conduit---looming/a5915b122640/dorman-conduct-tite-3-8-inch-black-wire-conduit/cti0/86663 https://www.oreillyauto.com/detail/c/dorman-conduct-tite/lig...