Optoma's EzPro 585 is known for its classic design, and unique features.  The EzPro 585 is one of the best selling projectors for corporate, school and government audio/video applications.  The EzPro 585 is a classic projector that combines remarkable brightness and affordability.  All Purpose Multimedia Projectors Features Monitor Loop Through Real Plug & Play with Auto Sync Universal Power Supply     The EzPro 550 has true SVGA 800 X 600 resolution and 1,024 X 768 XGA resizing capability.  Compatible with notebook PC, and MAC computers, the EzPro 550 is the total solution for mobile multimedia presentations.  Supported by OPTOMA's three-year-standard warranty, the EzPro 550 is designed to be the most economical solution for presentation and audio-video applications. Most Economical Multimedia Presentation Solution Compatible with PC, MAC and Notebook Computers Equipped with Monitor Loop Through Deluxe Wheeled Carrying Case