The PowerBook Duo is a line of subnotebook computers introduced by Apple Computer in 1992 and sold until 1997. Designed as a smaller companion to the PowerBook 100 series and the later 500 series, the line comprised seven models: the PowerBook Duo 210, 230, 250, 270c, 280, 280c, and 2300c.
Weighing 4.1 pounds (1.9 kg) and measuring 10.9 by 8.5 inches (280 by 220 mm), the PowerBook Duo was the smallest and lightest PowerBook of its time. To achieve its compact size, it omitted many built-in ports and expansion features, instead relying on optional docking stations to provide additional connectivity and functionality.
The PowerBook Duo line was discontinued in 1997 and replaced by the PowerBook 2400c, which incorporated more built-in functionality but did not support the Duo docking system.