We tend to use the term "mobile phone booster" for pretty much anything that improves mobile coverage / signal. But there are actually two different devices - the booster and the repeater.
The Booster - connects by cable to a mobile phone and amplifies (boosts) the incoming and outgoing signal.
The Repeater - picks up the mobile signal, amplifies it, and then re-transmits the signal to mobile phones / devices nearby.
In our website, we refer to Cel-Fi "boosters" - technically this is wrong as they are actually repeaters. The only reason we do this is that people more commonly talk about boosters, rather than repeaters.
The ONLY legal repeaters in Australia are made by "Nextivity" and marketed as Cel-Fi.
ALL "Boosters" are illegal in Australia (ie. units that connect to your mobile phone and amplify/boost the signal - other than simple antennas)