Universally compatible coiled handset cord with all telephones manufacturers including AT&T, Cisco, NEC, Rolm, ITT, & Tie.You can use them as replacements for those and Avaya 5420 and 5610SW IP phones. The phone line detangler automatically rotates 360 degrees to effectively prevent your coiled handset cord from being tangled and messed up, and you would not feel frustrated with entangled cord, make your phone cords tangle free, stop untangling twisted telephone cords. Ideal replacement for your telephone's handset cord, high-quality sound with noise-cancelling. Made of Pure-copper material, much better than normal Iron or Copper-clad-Steel telephone cord. The landline telephone cord cable is used between handset and telephone, not from telephone to wall plug. Applies to family fixed telephone, RJ11 plug 4P4C, not applies to VOIP phone , not fit for RJ45 modular plug. The phone handset cord is good to long-distance communication for your desk phone or office phone. Telephone extension cord is provided extra length for working in the office or at home.