Internet Explorer sp1 description
Internet Explorer - Internet browsing package from Microsoft

Internet Explorer 6 SP1 is the next update to the Internet Explorer technologies representing general improvements to Internet Explorer 6. Internet Explorer 6 SP1 includes a well-tested collection of updates that focuses on a variety of customer-reported concerns with Internet Explorer 6. Internet Explorer 6 SP1 includes all prior updates and patches as well as enhancements to reliability and security.

Note: This is not needed for XP users who have installed the Windows XP SP1. IE 6.0 SP1 in included.