A transpirator was a device used as an assist for the respiratory system, similar in form and function to a breath mask. It was known to be used by members of the Muun species. In 67 BBY, Darth Plagueis wore a transpirator mask to protect his respiratory system from the superheated air of the Bal'demnic grotto, where he and his master, Darth Tenebrous, who wore a similar mask, were inspecting cortosis deposits. After an attempt on his life by Maladian assassins 15 years later left Plagueis with a severed trachea and a large part of his jawbone missing, he was forced to wear a transpirator mask permanently until the end of his life. The device was affixed to the upper part of his chest and protected by an armored torso harness.