Use a Mac Computer with PC VGA monitor. 10 Dip Switches for resolutions setting: from 640 X 480 to 1152 X 870 DB15 Male to HD15 Female Use a Macintosh with pc monitor. Plug your PC VGA Monitor to a Mac! MAC/VGA ADAPTER BLOCK HDDB15F/DBM 15P WITH SWITCHES Allows Mac's and Power PC's to interface with VGA, SVGA and Multisync Monitors. Simple switch settings for resolutions from 640 X 480 to 1152 X 870 SYSTEM AND OTHER REQUIREMENTS Compatible with VGA and Multisync SVGA Monitors Supports all Mac's with DB15 Video Ports.