DM Categories Dropdown allows you to list K2 categories inside a dropdown or a listbox within a Joomla module. You can choose to list categories (and, if you want, their subcategories in a structured list) having a particular parent. In addition, the module can show an intro text, a link at the bottom, the articles' creation date. You can choose to have the active item always selected; SEF is supported with native Joomla API.