This top of the line CB speaker is designed specifically for the Cobra 25, 29, 148 and Uniden PC 66, 68, 76, 78 series radios due to the talkback feature, this feature is not compatable with radios not listed here.
If you want the same quality and noise canceling properties but don't have one of the listed radios, consider the Cobra HGS300. The noise canceling feature this speaker and the 300 offer will effectively reduce the amount of unwanted background noise, a subtle but nice feature over standard external speakers.
The talkback function allows you to hear your transmissions during transmit, your voice will come through the speaker while talking. This can be a useful tool to make sure your radio is functioning correctly, if you hear your voice there is a good chance you are transmitting.