Designed to alert the user to hazardous noise levels, the Noise Indicator N1-100 provides real-time noise detection. The detector clips to clothing and alerts to unsafe noise levels with a LED light, signaling when hearing protection may be required. A Popular Science "Best of What's New" in 2011, Noise Indicator NI-100 is designed to alert users to hazardous noise levels. It clips to clothing and uses a LED light to offer real-time noise detection, signaling when hearing protection may be required. Innovative and durable noise detection, the NI-100 noise indicator alerts you when noises in an area reach potentially hazardous levels. The noise indicators small size and lightweight design make it ideal for workers in a variety of industries. With a rechargeable battery that operates for up to 200 hours between charges, its an economical investment in your hearing conservation program. The NI-100 can be used as an effective training tool within a Hearing Conservation Program (consult OSHA Standard 1910.95) to help ensure workers know when and where to wear hearing protection. Safety and health professionals can also use it as a mapping tool to determine where noise studies are necessary. In a variable noise environment, the 3M noise indicator can help train workers as to when noise levels become potentially hazardous and hearing protection may be required.