42 Testing of electrical and electronic navigational aids, namely, offshore marine navigational aid services namely providing certified field inspections and maintenance records,providing research, engineering and design consulting services for others relating to marine and aeronautical navigational aids, namely; explosion proof equipment, visual and audio signaling apparatuses, supervisory control and data acquisition (SCADA)-Telemetry, Cathodic protection,installation and replacement, and the monitoring of fire detection,smoke detection, and gas detection system installation, maintenance/services and the remote monitoring thereof