An apparatus for facilitating delivery of conditioned air across a barrier in a cage for holding an animal patient to a blanket arrangement providing the conditioned air to the patient. The apparatus comprising a first duct part, a second duct part and a mounting mechanism arranged to mount the first duct part on one side of the barrier and the second duct part on the other side of the barrier opposite thereto, to provide a duct for ducting conditioned air across the barrier. The barrier comprising bars or mesh, and the apparatus further comprising a seal arrangement to provide at least a partial seal across the bars or mesh. The mounting mechanism comprises a fastening mechanism for fastening the first and second duct parts to each other across the barrier, wherein the fastening mechanism is a keyhole-style fastening arrangement utilising a plurality of headed projections on a flange of the first duct part engagable with respective keyhole-style apertures on a flange of the second duct part.