Emits Sound At Multiple Frequencies Attenuated Above 4000Hz Warning Signal Is More Directional And Perceived To Dissipate Quicker Than Pure Tone 97 Dba Sealed In Epoxy For Protection Against Dust, Moisture, And Vibration Temperature Range: -40 Degrees Fahrenheit To +185 Degrees Fahrenheit (-40 Degrees Celsius To +85 Degrees Celsius) Ea5200 Multi-Frequency Back-Up Alarms Provides A Solution To Potential Noise Pollution Created By Conventional Tonal Back-Up Alarms In Confined Or Densely Populated Work Areas. Those Multi-Frequency Alarms Maintain A Safe Warning Signal For Those In The Danger Zone Of Backing Vehicles While Minimizing Disturbance To Work Site Neighbors. Multi-Frequency Alarms Operate By Emitting Sound At Multiple Frequencies Attenuated Above 4000Hz.