Rarely used, three times. Works great and is in great condition. No signs of use/wear. Simply not used or needed. Buyer pays shipping. The 598U USB modem supports: Microsoft Windows XP, Windows Vista, Mac OS X version 10.4.11 or higher, and Linux (for Linux information, please see the website for Sierra wireless). TRU-Install technology from Sierra Wireless simplifies the installation process by placing all the necessary drivers and software on the modem – no CD is required. The software installation wizard begins automatically after you insert the modem into a Windows or Mac computer. In areas of weak coverage, an external antenna (sold separately) can boost signal strength. The antenna connects directly into the 598U USB modem via the robust antenna connector located on the side of the modem. To purchase an external antenna, visit the online store. For current updates, visit Sprint website. Select Mobile Broadband Devices, then select 598U by Sierra Wireless. Select your Operating System and then click More details. Click Download. Thank you for considering this purchase.