UHF CB is a class-licensed (meaning licence fee free use for most users) citizen's band radio service authorised by the governments of Australia and New Zealand in the UHF 477 MHz band. UHF CB provides 77 channels, including 32 channels (16 output, 16 input) allocated to repeater stations. It is similar in concept to the 40 channels used in United States' HF CB allocation, which is also available in Australia and New Zealand.
User equipment designs are similar to commercial land mobile two-way radio. Except for repeater stations and stations using the data-only channel, the maximum legal output power is 5 Watts. External antennas are permitted and common commercially manufactured antennas have gain as high as 12dB. Handheld transceivers (walkie talkies) are permitted and have transmit power from 500 mW to 5W (full legal power) and are relatively cheap compared to full-sized transceivers.
Other similar personal radio services used in other countries do not share the same band plan, power output, channels etc. as UHF CB. It is usually illegal to use these systems in Australia and New Zealand because they will interfere with other licensed services. Care must be taken with radios imported from overseas to ensure they comply with local regulations.
Read more about UHF CB: Selective Calling (Selcall), Continuous Tone Coded Squelch System (CTCSS), Repeaters, Channel Use, New Zealand