CBWI October 2001 RF Limited XTR-2018 Xtreme™ Echo Mic
Xtreme 2018 EC-2018XTR Mic for CB Radio 4 Pin | eBay
EC-2018XTR Xtreme echo microphone
The EXtreme 2018 Ultimate CB Radio, Echo Microphone, with noise reducer option, demo/review - YouTube
RF Limited (EC-2018-XTR) - Power Microphone with Xtreme Digital Echo, Noise Reducer and TalkBack, Black, Factory Wired, 4-Pin Cobra-Uniden, Mobile Comm. Microphones
Xtreme 2018 EC-2018XTR Mic for CB Radio 4 Pin | eBay
EC2018 Xtreme Mic | Copper Electronics
Turbo Extreme Microphone with Echo Control | Walcott Radio