Matrox Dual Head 2 Go DualHead2Go Digital ME inc cables (mini-DVI dual monitor)

Matrox part number D2G-DP2D-MIF. Maximum DVI Resolution 3840×1200 (2x 1920×1200). Connect two monitors to MacBook, MacBook Air or MacBook Pro with mini-display port. Powers by usb. Single Mini DisplayPort / Thunderbolt™ video output on a compatible system.

eBay