Monitor Worker Safety: As with all Vertex Standard radios, the VX-450 series includes built-in Emergency and Lone Worker alerts. Emergency notification is user-initiated with a press of a button for the radio to switch to a designated channel and send an alert for help. Lone Worker mode is a built-in timer that requires the user to reset at a predetermined interval. If not reset, the radio automatically switches to Emergency mode to alert help. When constant contact is required at all times, Vertex Standard’s exclusive Auto-Range Transpond System (ARTS) is included to inform the user that other ARTS- equipped radios are within communication range. No two job sites are alike and the optional Man Down function (with DVS-9 unit) is programmable to monitor a variety of worker timed safety scenarios vertically and horizontally as well as worker degree of motion. Adjusting the settings of the 3-axis sensor adapts the radio to each distinct work environment to monitor movement. Solid Build for Extreme Environments: The VX-450 Series withstands job site abuse meeting military standards for ruggedness and meets the IP57 ingress protection standard where water does not harm the radio when submersed to a depth of 3 feet for up to 30 minutes. IP57 water submersion rating valid only with accessory cover attached. Intrinsically Safe Option for Hazardous Locations: Intrinsically safe models are SGS certified to the requirements of ANSI/UL913 5th Edition for use in Class I, II, III, Division 1; Groups C, D, E, F, G; Temp T3C hazardous locations. Audio and Voice Responsiveness: Features 700 mW loud audio output ideal for noisy work environments. Includes Channel Announcement which loudly speaks the channel description to simplify changing channels when focused on other tasks simultaneously. Features voice activation (VOX) when used with MH-81A4B headset that enables users to transmit voice without pressing the Push To Talk button for hands-free operation.