Abstract: The invention relates to a connection box for an air line in a ventilation or air-conditioning installation, having a housing which comprises a housing wall consisting of a plurality of housing-wall regions, said housing having at least one inlet and at least one outlet. The housing can be collapsed, pushed together and/or folded in order to reduce the volume taken up by the housing, and that in the region of the inlet there is provided a flap which is mounted in the inlet such that it can pivot about a shaft or axle, which is arranged in particular centrally with respect to the opening, between an open position and a closed position and extends in its closed position at least over a substantial part of the flow cross section of the inlet, in particular completely closes the flow cross section of the inlet.

Abstract: The invention relates to a flap, in particular a throttle flap, for influencing a volumetric flow flowing in a ventilation and air-conditioning system. In order to specify a flap which has a simpler design and can additionally be produced and also mounted more easily, the intention is for the flap to be arranged in an installation frame having an opening and for the flap and the installation frame to form a mounting unit, wherein the flap is mounted in the opening such that it can pivot about a shaft or axle arranged centrally, in particular, with respect to the opening, and for the installation frame and the flap to each be produced from plastic.