AcoustiShield, a multi-stage automotive insulation sound-dampening material, is installed next. This material keeps noise, along with heat and cold, out. Imagine driving in a heavy rain and not hearing the sound. That's how good this sound-dampening system is. Dynamat heads off the initial road boom and slipstream noise. AcoustiShield soaks up the rest, including temperature. This is the same kind of material used in jetliners to keep noise and cold out at high altitudes.