WTA Tier II tournaments

The WTA Tier II tournaments were Women's Tennis Association tennis second-level tournaments held from 1990 until the end of the 2008 season. The line-up of events varied over the years, with tournaments being promoted, demoted or cancelled. 
From 2009 WTA Tour, WTA changed tournament categories, so that majority of Tier I and Tier II tournaments from the previous season are in one category, WTA Premier Tournaments.
External links.
https://www.grandslamhistory.com/atp/wta-tier-2