Long vertical telescopic tubes on which the necessary aerials are mounted so that a submarine can operate radio or radar when submerged at periscope depth.
Izibonisi kude ezinde ezithe ngqo apho, eziyimfuneko zilayishiwe ukuze iinkwili zibe nokusebenza ngonomathotholo okanye izixhobo ezibonisa inqwelo moya xa zihlanganiselwe kubunzulu bombhobho omde onezilanga zokubona phezulu xa imboni isezantsi ingakumbi enkwilini.