Pipe Threader Set, a Ratchet Die Stock / Tube Threader Set.

This tool is used to cut threads into the ends of metal pipes, allowing them to be securely joined with fittings or couplings. It's a critical tool for ensuring secure, leak-proof connections in various applications like plumbing, gas lines, and HVAC systems. The set typically includes a range of threading dies and a handle for creating threads on pipes of different sizes. Manual pipe threaders are widely used in plumbing, construction, and industrial applications to create screw threads on the exterior of pipes.