They are known as PMR-446 radios and they work between the frequency band 446.0 - 446.1 MHz. They used to have a Max transmit power of 500mW, and an approximated range of 5 km in optimal conditions.
The PMR (Private Mobile Radio) 446 service has been introduced following the adoption by the CEPT/ERC1 of the Decisions ERC/DEC/(98) 25, 26 and 27 which comply member states to:
a) Set aside the band 446.0 - 446.1 MHz for a PMR 446 service, with a channel plan based on 12,5kHz spacing:
F1 = 446,00625 MHz.
F2 = 446,01875 MHz.
F3 = 446,03125 MHz.
F4 = 446,04375 MHz.
F5 = 446,05625 MHz.
F6 = 446,06875 MHz.
F7 = 446,08125 MHz.
F8 = 446,09375 MHz.
b) Users do not require a licence to use PMR 446 radios.
c) Allow the free circulation and use of PMR 446 equipment using frequencies in the 446.0 - 446.1 MHz band and complying with the European technical standard ETS 300 296.
d) The equipment shall use only integral antenna and an effective radiated power not exceeding 500mW.
This use has the consideration of common use.
It is used mainly for commercial or recreational activities, being able to enjoy economic, fast, trustworthy, simple and practical a communication.
It is the most reasonable way to remain in constant contact since license is not needed to use this portable equipment, that can be taken to any part.
The following accessories can be used with PMR 446 radios: external microphones including VOX type microphones; earphones, headphones and external loudspeakers; and DC power sockets, charge sockets and battery packs.
The accessories must be connected by appropriate sockets installed by the manufacturer at the time of manufacture and conformance evaluation and their use must not affect the RF characteristics of the radios.
In all cases, the use of these facilities must not cause any change to, or effect on, the performance characteristics of the PMR 446 radio, as permitted under the Wireless Telegraphy (Exemption) Regulations (SI 1999/930).