ATX cases are computer enclosures designed to house and protect the internal components of a desktop computer. They follow the ATX motherboard standard, which specifies dimensions and mounting points, ensuring compatibility with various hardware. These cases come in different sizes, such as full-tower, mid-tower, and mini-tower, allowing users to choose based on their needs and available space. In addition to housing the motherboard, ATX cases provide slots for graphics cards, storage drives, and power supplies. They often include features like cooling fans, cable management options, and front panel ports for easy access to USB and audio connections, enhancing both functionality and aesthetics.