Huskvana 125BV. My vacuum tube has 4 slots that slide over tabs on the circular surface of the air intake. The tab shoulders prevent the tube from being rotated either clockwise or counterclockwise; as you try to rotate the tube, the sides of the slots rest against the side shoulders of the tabs and I cannot rotate the tube over the shoulders of the tabs. I feel really stupid as I'm sure there's an easy way to do it.