ERECTOR COLLAR Original Metal Part (Left) vs. Mira Plastics' Resin Part (Right) The use of modern engineering plastic resins allows for the conversion of metal to plastic parts. These resins can be pre- colored to match your end use application. This conversion eliminates the need for costly, heavy, die cast metal parts, as well as secondary operations such as cutting, threading, drilling and painting, while maintaining part integrity and mechanical functions.