K40 refers to a specific type of laser cutter and engraver that is popular among hobbyists and small businesses. It typically uses a CO2 laser to cut and engrave various materials, including wood, acrylic, and leather. The K40 is known for its affordability and compact size, making it accessible for those new to laser cutting. The K40 machine usually comes with a working area of about 12x8 inches, allowing for small to medium projects. Users often modify the K40 to enhance its performance, such as upgrading the laser tube or adding better cooling systems. This versatility has made it a favorite in the maker community.