The 227-1221-9 is a hex crimp die used for terminating RF connectors onto coaxial cables in connector assembly operations. This die is manufactured from tool steel and heat-treated to Rockwell C52-60 hardness, with a black oxide coating on crimping surfaces per MIL-C-13924 to ensure durability and corrosion resistance. The die features a dimension "A" of 0.068 inches and dimension "B" of 0.068 inches, with a dimension "C" of 0.400 inches, designed to work with RG-series cables and BNC, TNC-CAV, SMA-CAV, and UNC-CAV connector series. It is used in conjunction with Amphenol tool frame part number 227-944 and operates at fully butted conditions per MIL-C-22520/5C specifications. This die is essential for RF cable assembly operations requiring precise and reliable connector termination in telecommunications, aerospace, and military applications.