5.7cm (2.2") miniature speaker with waterproofed, transparent Mylar membrane and Neodymium-magnet. Light weight. Low installation height. Can be used outside and at critical environments. Suitable as signal speaker at electric machines. Good speech, intelligibility.Typical applicationsVoice and signal output in machines and other equipment where space is at a minimumTransducer Function: SpeakerDriver Type: MiniaturePower Rating RMS: 2WExternal Diameter - Metric: 57mmImpedance: 8ohmSensitivity (dB): 87dBResonant Frequency: 550HzFrequency Response Min: 350HzPower Rating Nom: 2WFrequency Response Max: 6.8kHzSound Level SPL: 87dBASpeaker Shape: RoundExternal Diameter - Imperial: 2.244"Speaker Mounting: Bare MountPower Rating Max: 3WExternal Depth - Metric: 17mmExternal Depth - Imperial: 0.669"