A hacksaw is a hand tool used for cutting hard materials, primarily metal and plastic. It consists of a frame that holds a thin, serrated blade under tension. The blade's teeth are designed to cut through tough materials, making hacksaws ideal for tasks like plumbing, metalworking, and DIY projects. Hacksaws come in various sizes and blade types, allowing users to choose the right one for their specific needs. The blades can be easily replaced when worn out, and the tool is commonly used in conjunction with other tools like files and saws for more complex tasks.