This adjustment arm bar is one of the parts coming with Transcend
H9M Waterless Humidification System
and Transcend H6B Travel CPAP Machine Waterless Humidifier
. The H9M and H6B systems have three sizes (S/M/L) in the package.
Note three different size bars used to sell individually but now this replacement part has three sizes of bars (small, medium, large) in one package so you can always find the right one you need.