The Union Butterfield 14-10240 is a 1/4"-28 NF (UNF) right-hand hex rethreading die (also known as a die nut). It belongs to the manufacturer's Series 2025 tool line.
Tool Specifications
Thread Size: 1/4"-28
Thread Standard: NF / UNF (Unified National Fine)
Series: 2025
Material: Carbon steel or chromium steel
Finish: Bright / uncoated (improves chip flow in soft metals)