Compaq iPAQ 216198-B21 Dual Slot PC Card Expansion Pack for 3600, 3700, 3800, 3900, 5400 series Increase the file storage space on your iPAQ Pocket PC Access your company's wireless network (WLAN) for e-mail and Web browsing Access the Internet wirelessly through the cellular phone system Provides twice as much battery power as the PC Card Expansion Pack to run your PC Cards or to extend the life of your iPAQ Pocket PC Holds two Type II or one Type III PC Cards that are compatible with the Pocket PC operating system