IEC 60793-2-40:2009 is applicable to optical fibre categories A4a, A4b, A4c, A4d, A4e, A4f, A4g and A4h. These fibres have a plastic core and plastic cladding and may have step-index, multi-step index, or graded-index profiles. This third edition cancels and replaces the second edition published in 2006 and constitutes a technical revision which defines an enhanced A4a fibre named A4a.2 while the existing A4a fibre has been renamed A4a.1.