Bush

Metal threaded sleeve usually brass or stainless steel, with a round or hexagonal flange face. Used to secure or fix heating elements in place. Crimped using special dies for Dry applications.

Silver Soldered for Wet applications. 

Compression Bushes, are secured using spanners to tighten a cap nut compressing a brass olive onto the sheath. This is suitable for wet and dry applications and performs well under pressure and in vacuum.