Abstract: A platinum curing organosiloxane composition having improved hysteresis characteristics when cured. The composition requires the presence of a diorganovinylsiloxy terminated polydiorganosiloxane having a viscosity within a range of about 20 Pa.multidot.s to 200 Pa.multidot.s at 25.degree. C. and containing essentially no ethylenically unsaturated hydrocarbon radicals bonded to non-terminal silicon atoms and a diorganovinylsiloxy terminated polydiorganosiloxane having a viscosity within a range of about 0.1 Pa.multidot.s to 200 Pa.multidot.s at 25.degree. C., where from 1 to 5 percent of the non-terminal repeating units of the siloxane comprise a vinyl radical. In addition, the present composition comprises 10 to 30 weight percent of a reinforcing silica filler that has been treated with hexamethyldisilazane and 1,1,3,3-tetramethyl-1,3-divinyldisilazane, and an organohydrogen siloxane crosslinker comprising at least ten silicon-bonded hydrogen atoms per molecule.

Abstract: A flexible seal (2), particularly for use in pneumatic testing of cigarettes, includes a conical seat (6) attached to a tube (4) having a resilient collar (8). The collar permits longitudinal movement of the seat relative to the tube, thereby permitting an effective seal against the cigarette being tested, and contributes to extended life for the seal.

Abstract: A facemask incorporating breathing equipment for use with a flying helmet (2) comprises a rigid outer shell (4) in which a flexible face-piece (3) is housed whose periphery makes an airtight seal with the pilot's face (1). The face-piece (3) includes an inhalatory valve (11) and an expiratory valve (9) and the rigid shell (4) is attached to the helmet (2) by a harness (5) which keeps the shell (4) at a fixed distance from the helmet (2). Inflatable means (15, 20) are provided between the shell (4) which are inflated to press the periphery (14) of the face-piece towards the pilot's face when the pressure of breathable gas supplied to the interior of the mask and to said inflatable means increases above that required for normal breathing.

Abstract: An under helmet hood for aircrew which has a butyl rubber cowl (1) and, severed but in no way displaced therefrom, a face mask portion which includes a face mask (2) having a fixed vizor (3). The perfect butt joint remaining in the butyl rubber between the cowl (1) and the face mask portion is covered by a longitudinally grooved neoprene strip (5), glued in position during manufacture before the cowl is severed, having a rip toggle arrangement which enables tearing of the strip along its groove (9) to be initiated. The face mask portion is then readily ripped out by further tearing of the strip along its groove and separation of the face mask portion at the butt joint. The invention enables reliable protection against all NBC agents and yet at the same time affords excellent rip off facility.