Dayton Audio DAEX25VT-4 Vented 25mm Exciter 20W 4 OhmDayton Audio's 25 mm DAEX25VT-4 coin type exciter features the same ability to turn nearly any surface into a speaker, as other exciters and tactile transducers, only in a more compact package for working with smaller surfaces. This exciter's small size enables audio reproduction in places never imagined: toys, monitors, cabinet doors... even windows! A neodymium magnet is employed to create maximum magnetic flux around the proprietary voice coil for increased sensitivity when compared to similar sized exciters. In turn, this reduces power requirements and makes it possible to use very small audio amplifiers, without sacrificing total output. The 1" voice coil, and cooling vents, allows for more input power for higher output applications while maintaining a slim-line form factor. To ensure maximum acoustic energy transfer between the transducer and the surface to which it is attached, 3M VHB (Very High Bond) adhesive is pre-applied... just peel and stick! Two PCB solder points keep installation and wiring as compact as possible. Note: An exciter's frequency response and sensitivity are completely dependent on the exciter's designated surface. Thinner, smaller materials will tend to be louder and create a mid/tweeter response. Thicker, larger materials (with multiple exciters) will be slightly quieter but result in a more full-range sound. Specifications: - Power handling: 20 watts RMS - VCdia: 25 mm - Nominal impedance: 4 ohms - Re: 4.2 ohms - Le: 0.24 mH - Fs (uncoupled): 292 Hz - Dimensions: 2.02" (51.4 mm) dia. x 0.81" (20.5 mm) H - Adhesive dimensions: 1.10" (28 mm) outside diameter, 0.85" (21. 5 mm) inside diameter - Weight: 77.5 grams.