produced is the desired shape of the uninflated cuff 8 that is an elliptical ring with a concave channel extending around its upper surface the inflated shape of the cuff 8 can be slightly different from its uninflated shape because the reinforcing members 36 allow preferential inflation in the unreinforced regions after passing through the lower forming station 34 the two tracks 21 and 22 come together at a third station 40 the third station 40 has a supply hopper 41 of the rigid mount members 7 attached with the inflation lines 3 and their inflation indicators and connectors 4 these are conveyed along a short belt 42 extending alongside the two tracks 21 and 22 the third station 40 positions the mount members 7 between the formed cuff members 9 and 8 on the upper and lower tracks 21 and 22 so that the mount members are located between the two cuff members the upper and lower tracks 21 and 22 now proceed together to a fourth station 50 where the members on the upper and lower sheets are joined to the mount members 7 and cut out from their respective sheets this may be done by a push fit arrangement by welding by a cut punch arrangement or by a combination of any of these the completed mask assemblies 2 are then ejected onto another conveyor belt 51 where they are carried to a subsequent station not shown for assembly onto the tube 1 in a conventional manner the cuffs 8 and 9 could be filled with a foam material so that they have a naturally inflated state and are sucked down to deflate it for insertion or removal the foam could be added by injecting a liquid.