For current serials, the extent of item (subfield $a) contains only the specific material designation, which for printed serials is "v." Note that while AACR2 12.5B1 in the revised edition indicates that the serial may be described as "v.", "no.", or "pt.", LCRI 12.5B1 says to describe all serials as "v." This is because the earlier version of AACR2 included only "v." and LC decided not to change its practice. Example:

See also:

11.1. Extent of item