The 227-1221-57 is a die set component for the Amphenol TWINHEX crimp tool system, designed for use with both the hand tool frame 227-944 and the pneumatic crimp tool 227-60. This die set features a hexagonal outer cavity (Cavity A) of 0.213 inches (5.4 mm) and an inner cavity (Cavity B) of 0.100 inches (2.5 mm), enabling precise crimping of specific RF connector and cable assemblies. The die set is compatible with military standard M22520/5-57 specifications and is sold separately for integration into the TWINHEX system. It is commonly used in industrial and military standard applications requiring high-precision RF connector assembly with consistent crimp quality.