Cat7 cables use an S/FTP construction in which every pair is individually foiled and the whole bundle is braided, certified to 600 MHz under ISO/IEC 11801 Class F, while Cat7+ (Class FA) extends that to 1000 MHz. The dual-layer screening gives per-pair noise immunity in electrically noisy environments such as manufacturing plants, hospitals and broadcast infrastructure. To preserve that performance the screen continuity must be carried through to earth at both the panel and outlet ends; PE-jacketed outdoor versions are used on direct external routes.