Introduced in the late 1990s, the MicroATX is basically a smaller version of Intel's ATX specification, intended for compact, low-cost consumer systems with limited expansion potential. The maximum size of the board is 9.6" square, and it's designed to fit into either a standard ATX case or one of the new micro-tower desktop designs. The double-decker I/O shield is the same as that on the ATX design, but there's only provision for up to four expansion slots as compared to the seven that ATX allows. The microATX also allows use of a smaller power supply, such as the SFX design, which is reduced both in size and power output.