&lt;p&gt;TOA&amp;#039;s CS-64 CS-154 and CS-304 speakers are for outdoor-use they use wide-range horns that can provide background music or paging announcements which have high quality sound. They are designed to produce high output with an increase of the speaker acoustic conversion efficiency by the use of a horn in combination with a cone speaker. The CS-64 employs an exponential horn while the CS-154 and CS-304 use constant directivity horns (90 horizontal) to control sound directivity realizing uniform and clear sound dispersion over a wide area.&lt;br /&gt;&lt;br /&gt;&amp;bull; Exponential horn improves directivity characteristics and ensures uniform and clear sound dispersion. &lt;br /&gt;&amp;bull; Lightweight ABS resin enclosure that is mechanically strong and resistant to impact. &lt;br /&gt;&amp;bull; Weatherproof polyurethane resin paint permits the speaker to stand up to many years of outdoor installation. &lt;br /&gt;&amp;bull; Stainless steel hardware protects the speaker from corrosion. &lt;br /&gt;&amp;bull; The enclosure complies with IP-64 Standards for dust proof and waterproof characteristics. &lt;br /&gt;&amp;bull; Rotary impedance selector switch facilitates external changes in impedance during and after speaker installation.&lt;/p&gt;&lt;table class=features&gt;&lt;thead&gt;&lt;tr&gt;&lt;th colspan=2&gt;Features&lt;/th&gt;&lt;/tr&gt;&lt;/thead&gt;&lt;tbody&gt;&lt;tr&gt;&lt;td class=feature&gt;Type&lt;/td&gt;&lt;td&gt;Horn  &lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td class=feature&gt;Single/ Pair&lt;/td&gt;&lt;td&gt;Single  &lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td class=feature&gt;Outdoor horn&lt;/td&gt;&lt;td&gt;Yes  &lt;/td&gt;&lt;/tr&gt;&lt;/tbody&gt;&lt;/table&gt;