Abstract: A hollow stranded wire (2) has a first layers (4) and second layers (6). The second layer is located outside the first layer. The first layer is formed by twisting eight first element wires (8) which are flat wires. The second layer is formed by twisting eight second element wires (10) which are flat wires. A ratio (Ww/Tw) of a width Ww to a thickness Tw of each flat wire is from 2 to 11. A twisting direction of the second element wires is opposite that of the first element wires. A twisting angle of each first element wire is not greater than 85°. A twisting angle of each second element wire is not greater than 85°. A ratio (D/T) of an average diameter D to a thickness T of the hollow stranded wire is not less than 5 and not greater than 20.

Abstract: A hollow stranded wire (2) has a first layers (4) and second layers (6). The second layer is located outside the first layer. The first layer is formed by twisting eight first element wires (8) which are flat wires. The second layer is formed by twisting eight second element wires (10) which are flat wires. A ratio (Ww/Tw) of a width Ww to a thickness Tw of each flat wire is from 2 to 11. A twisting direction of the second element wires is opposite that of the first element wires. A twisting angle of each first element wire is not greater than 85°. A twisting angle of each second element wire is not greater than 85°. A ratio (D/T) of an average diameter D to a thickness T of the hollow stranded wire is not less than 5 and not greater than 20.

Abstract: A probe needle for a probe card which is characterized by applying a Ni plating containing PTFE to at least an end face of a tip portion thereof is disclosed. A Ni plating containing PTFE layer may preferably be formed on the tip portion of the probe needle by using a Ni plating layer as a substrate. The Ni plating may preferably have a thickness of 0.5-2 &mgr;m to ensure the adhesion of the Ni plating containing PTFE, while the Ni plating containing PTFE may preferably have a thickness of 0.5-2 &mgr;m to ensure the sliding property of the PTFE. In this probe needle, since the tip portion thereof is covered with the Ni plating containing PTFE layer, the wear resistance is not deteriorated, the favorable conductivity is obtained, and the oxidization of the end face which is brought into contact with an integrated circuit is prevented.