Micro ATX is a motherboard form factor that measures 244 x 244 mm (9.6 x 9.6 inches). It is designed to provide a balance between size and expandability, making it suitable for compact desktop computers. Micro ATX boards typically feature up to four expansion slots, allowing users to add components like graphics cards and sound cards. This form factor is popular among gamers and general users who want a smaller case without sacrificing performance. Many PC cases are designed to accommodate Micro ATX motherboards, providing flexibility in building a custom computer system.