Other crossword clues for answer "PERISCOPE"PERISCOPESub apparatusSubmarine's viewing instrumentSherman tank deviceTubular submarine deviceSub viewerOptical instrument used in trenches.Nautilus adjunct.Optical instrument with mirrors.Optical instrument at sea.Submarine instrument.Seagoing eyeView-finder for RickoverViewer on the NautilusMeans of looking above and beyondView enhancer