| 摘要 |
A set of ventilation units comprises a first and second ventilation unit, wherein a surface of the first ventilation unit is provided with at least one formation and a surface of the second ventilation unit is provided with at least one co-operating formation. The formation(s) and co-operating formation(s) is/are engageable with one another in a direction substantially perpendicular to said surface of the first ventilation unit and/or said surface of the second ventilation unit. |
