Atlas Sound SM42T-W 4" 2-Way Weather Resistant Speaker System With 70.7V/100V-16W Transformer 1 Ferrofluid Cooled Dome Tweeter Highly Efficient 4 Polypropylene Woofer. Atlas Sound POLYGUARD High Frequency Protection Circuit. Weather-Resistant Construction For Year-round Indoor or Outdoor Use. TRX WAVEGUIDE Constant Directivity Style High Frequency Wave Guide System. Screwdriver Adjustable 16-Watt 70.7V100V Transformer may be bypassed for 8-ohm operation.