Global Optical and Audible Signal Devices Market By Type (Strobe and Beacons, Signal Lights, Bells and Horns, Fire Alarm/Call Points, Speakers and Tone Generators, and Visual & Audible Combination Units), By Application (Oil and Gas, Chemical and Pharmaceutical, Food and Beverages, Energy and Power, and Mining), By Region, and Key Companies - Industry Segment Outlook, Market Assessment, Competition Scenario, Trends and Forecast 2019-2028