Aircraft and their structural parts and fittings thereof; railway rolling stock and their structural parts and fittings thereof; automobiles and their structural parts and fittings thereof; two-wheeled motor vehicles and their structural parts and fittings thereof; bicycles and their structural parts and fittings thereof; wheelchairs; machine elements for land vehicles, namely, drive shafts, axles and spindles for land vehicles, wheel bearings for land vehicles, shaft couplings or connectors for land vehicles, idling pulleys for land vehicles, reversing gears for land vehicles, reduction gears for land vehicles, belt pulleys for land vehicles, toothed wheels or gears for land vehicles, speed change gears for land vehicles, hydraulic torque converters for land vehicles, center links for suspension systems for land vehicles, pneumatic shock absorbers for land vehicles, land vehicle suspension components, namely, air springs for cushioning driver's seats and cabs, spring shock absorbers for land vehicles, spring assisted hydraulic shock absorbers for land vehicles, cone brakes for land vehicles, disk brakes for land vehicles, band brakes for land vehicles, and block brakes for land vehicles