Made of PVC copper. High quality sound quality, all copper plated gold needle core, stable transmission signal. Good contact and transmission performance, provide a strong guarantee for stable data transmission, easy to use, convenient connection, no static or sound distortion. | The front and back ends are made of environment-friendly PVC material to protect the internal chip structure, internal insulation, strong anti-interference ability and low signal attenuation coefficient. Oxygen free copper conductor has high fidelity sound quality, exquisite technology, strong anti-interference ability and low signal attenuation coefficient. | This product is used to connect and expand two existing telephone lines through the R11 telephone head (6p4c, 6p2c crystal head) at both ends through the telephone through box. | Thickened PBC board, strong and durable, to avoid the problem exposed damage, high temperature resistant, longer service life, to provide a good firm connection without loss of signal. | Compatible with all RJ11 devices, such as landline phones, faxes or answering machines. Assistant for home, study, living room, bedroom, office, business meeting, home entertainment and study.