Speco's  6" aluminum PA horn is weatherproof. It offers a frequency response of 250 to 15,000 Hz with a 10 watt RMS/15 watt maximum power rating. It features a 105 dB sensitivity and a 4 ohm impedance. Alternatively, it is available with an 8 ohm impedance under model number SPC-10. Technical Specifications Dimensions 6" (Dia) x 6" (L) Frequency Response 250-15,000 Hz Impedance 4 Ohm Material Aluminum Max Power 15 Watts Mounting Bracket Included RMS Power 10 Watts Sensitivity 105 dB

If You're Going to use this for Your CB Radio, You'll Need This  SPW10P