What is breaker 1-9?

"Breaker 1-9" is a slang expression used by truckers on citizens band (CB) radios to identify themselves and to request communication on a specific channel. "Breaker" means the speaker is trying to break into an existing conversation, while "1-9" refers to the channel number 19, which is commonly used by truckers for communication. The use of CB radios was popular among truckers in the 1970s and 1980s, but its use has declined since then due to advances in technology and the use of cell phones.