# Council Regulation (EC) No 21/2004 of 17 December 2003 establishing a system for the identification and registration of ovine and caprine animals and amending Regulation (EC) No 1782/2003 and Directives 92/102/EEC and 64/432/EEC, Division 6: The electronic identifiers must conform to the following technical characteristics:

Extent: E+W+S+N.I.

(a)they must be read-only passive transponders applying HDX or FDX-B technology, complying with ISO standards 11784 and 11785;
(b)they must be readable by reading devices, complying with ISO standard 11785, capable of reading HDX and FDX-B transponders;
(c)the reading distance must be:
(i)a minimum of 12 cm for eartags and marks on the pastern when read with a portable readers;
(ii)a minimum of 20 cm for ruminal boluses and injectable transponders when read with a portable reader;
(iii)a minimum of 50 cm for all types of identifiers when read with a stationary reader.

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Source: https://www.legislation.gov.uk/eur/2004/21/annex/division/A/division/6 (the official version)
Page: https://openlegislation.uk/eu-regulation-2004-21/annex/division-A/division-6
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.