Internal screen
Rolled-non-hermetic stainless steel cover, formed by profiling and rolling in a spiral, used as an internal screen to strengthen the structure, dissipate the temperature of the working environment to prevent damage to the main bellows.
Braided - is a steel mesh braiding, placed inside the bellows to disperse the temperature of the medium to prevent the damage of the main bellows.
PTFE - tube is used to prevent contact of highly corrosive environment with the bellows material, end fittings; as a rule, it is used in chemical industry, in working with acids, chemical compounds or highly adhesive environment.