Apple HDI-20 1.4MB PowerBook Duo Floppy Drive and MicroDock Adapter M8061 M7781
It is Apple model M8061 (part number 590-0719-A) and M7781. This drive and adapter will work with the PowerBook Duo 210, 230, 250, 270c, 280, 280c and 2300c, as well as the PowerBook 100 and Apple MiniDock.