Emergency Phones by Guardian Telecom are designed for critical communications in emergency applications. The HDE line of products or Heavy Duty Emergency phones are manufactured to work in harsh conditions including extremely cold weather, rain and noisy environments. The specially designed advanced circuit board will effectively allow reliable 2 way voice communication in noisy areas up to 92 decibels when used with an external power source. In order to combat moisture and dust from entering the enclosure, speaker and microphone areas, all of our HDE units have louvers which are very effective against rain, sleet, snow and dust. These louvers also prevent damage caused by vandalism to the speaker and microphone areas from sharp items such as an ice pick.