The Electro-Voice Model 636 is an omni-directional microphone of the dynamic type with only one moving element. The slim styling of the 636 was specifically designed to provide the flexibility and ruggedness required for general public address use. Incorporating the exclusive Electro-Voice Acoustalloy® dia­phragm material, the Model 636 is nearly impervious to extremes of temperature and humidity. The mechanical nesting principle of design by which the internal parts of the microphone are closely fitted one within another results in a mechanical structure that almost completely eliminates damage from mechanical shock.