This product is either discontinued or we cannot get that from suppliers.
Poly Plantronics Spare 40974-01, Cable Coil Mod, AV Cable Type Phone line cable, Black, Compatible With Poly M12 ¦ Poly CA 10.
Plantronics telephone connection cable for Adapters/Amplifiers. One side of this short cable has a modular plug that plugs into the Adapter, the other side has a modular plug that connects to the telephone.