The Imperial 400F positive stop gauge assures the correct size of any flare. Special burnishing action polishes flare face. Positive stop gauge assures correct size flare. Special burnishing action polishes the flare face. Three rollers in flaring cone reduce flaring effort and maintain original wall thickness during the flaring process. Three rollers in flaring cone roll out 37° flare above die block. Roller action cuts the effort required; maintains original wall thickness – eliminates stress concentration.