Star Wars Stormtrooper Darth Vader Mandalorian Fett helmet Voice Amplifier Please Note: Testing the unit with the mike unenclosed may result in a high pitched whine as the mike picks up the 'looped' sound coming from the speaker. This feedback will not occur when the mike is installed properly within a mask or helmet. Placing a cotton ball or piece of tissue over the mike will also help to eliminate the feedback. full-face respirators, these units are VOICE AMPLIFIERS, NOT VOICE CHANGERS. They offer NO VOICE DISTORTION, only amplification. These amps are manufactured to be used in emergency conditions when communication is crucial to saving lives. These are professional voice amplifiers that sell for $80 to over $100 retail!