For turnback wire rope splicing. Special processed low carbon steel. Turnback terminations have efficiency ratings of 94% based on the catalog strength of wire rope. Designed for lower temperature toughness. Resists cracking when swaged (equals or exceeds stainless steel sleeves). Cold Tuff for better swageability. Stamp for identification after swaging without concern for fractures (as per directions in National Swaging Brochure). - NOTE: S-506 Duplex sleeves are recommended for use with 6 x 19 or 6 x 37, IPS or XIP (EIP), RRL, FC or IWRC wire rope. Before using any National Swage fitting with any other type lay, construction or grade of wire rope, it is recommended that the termination be destructive tested and