The "double jacket" refers to an outer layer of insulation or protection added to the standard Cat5e cable. 1000ft Solid Ethernet Cable. 4-pair unshielded twisted pair (UTP) cable Copper-clad aluminum wire. 24AWG. Meet Cat5e Standard. Black Color Jacket Double Jacket: Waterproof Direct Burial Rated. Heavy-duty flexible double jacket to protect against cuts, scraps, and tearing Outdoor Use: The double jacket provides additional protection against environmental factors such as moisture, UV rays, and temperature extremes. Foot-marked cable is packaged in a pull box for easier installation