Vacuum is Dusty Hayes’s second mask, worn by the operator of Billboard Blast, and it creates pockets of vacuum energy. The fan wiki lists it in only three second-season episodes, and the sources describe the power in a single phrase.
The fan wiki notes that the mask looks the same as Backlash apart from the color, which suggests Kenner reused a mould for the Series 3 release. Our toy record lists a Vacuum Mask with Billboard Blast, 1987.