K2 is the popular, powerful and awarded content extension for Joomla! with CCK-like features developed by JoomlaWorks, makers of fine Joomla! extensions since 2006. It provides an out-of-the box integrated solution featuring rich content forms for items (think of Joomla! articles with additional fields for article images, videos, image galleries and attachments), nested-level categories, tags, comments, a system to extend the item base form with additional fields, a powerful plugin API to extend item, category and user forms, ACL, frontend editing, sub-templates and a lot more!