Disclosed is type THHN cable having a reduced surface coefficient of friction, and the method of manufacture thereof, in which the central conductor core and insulating layer are surrounded by a nylon sheath. This arrangement simplifies the structure and increases the stability, reliability, and service lifetime of vertical axis wind turbines by making on-site assembly easy and cutting the on-site workload and cost, without undermining the wind resistance capability and safety prompting wider application of vertical axis wind turbines. The interface information storage unit may comprise first and second registers storing interface information, which may be changed in response to an extension ROM BIOS executed during a booting operation. The method further provides for a profile of each strip to be filtered whereby the artifacts from a halftone screen are eliminated. The invention also concerns the use of said derivatives for keratinous fibre strengthening and care.