Irwin 9503 Hanson 1/4"-18 NPT Thread 1" Hexagon Taper Pipe Die (HCS) - Ideal for plumbing and air applications. 1" across flats. Ideal for maintenance and repair work. Recommended for use with hexagon die stock. Die can be used with a wrench or socket when space is limited. Advanced die geometry: Allows for faster cutting with longer life. Material types: High carbon steel (HCS) for cutting of external threads by hand. Etched: Die size is etched on each tool for easy identification.