Ink cartridges are small containers filled with liquid ink used in inkjet printers. They come in various colors, typically including black, cyan, magenta, and yellow, allowing for a wide range of printing options. Each cartridge is designed to fit specific printer models, ensuring compatibility and optimal performance. When the ink runs low, the cartridge needs to be replaced to maintain print quality. Some cartridges are refillable, while others are single-use. Proper disposal of used cartridges is important for environmental sustainability, and many manufacturers offer recycling programs to help reduce waste.