3M Noise Indicator NI-100

3M NI-100 3M

The NI-100 is a small, inexpensive and intuitive way to avoid the hearing loss that can plague everyone from professional construction workers to weekend garage tinkerers. Instead of a decibel meter that leaves the user to decide whether the ambient noise is dangerous, the device simply has an LED. When the noise reaches the potentially harmful level of 85 dBA, the light begins to flash red to alert the user to put on hearing protection. The 2-by-1.4-by-0.5-inch unit clips unobtrusively to a shirt and runs on a battery that lasts 200 hours between charges. $41