It's also commonly called a "Parrot" repeater.
The way they function is the repeater will record, some seconds to a minute or so, of the input audio stream. Then on termination of the reception it will re-transmit the audio just recorded usually on the same frequency.
These repeaters are less expensive due to the fact they don't need bulky and costly cavity filters, used to isolate the receiver from the transmitter, for true simultaneous reception and transmission of the audio stream. Some have built one for remote emergency communications.
https://www.youtube.com/watch?v=o05ILiIg5o4
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The negative aspect is the delay due to the necessity of recording the input audio stream and then the re-transmission. Many people find using a Parrot repeater rather irritating due to the delay.