Test tubes; holders for test tubes; cryogenic temperature monitors; cryostats for laboratory use; scientific, measuring and checking apparatus and instruments for the use in relation to the supply, storage and distribution of chemicals, gases and gas mixtures, in liquid or gaseous form, namely, flow switches for monitoring and controlling the flow of gases or liquids, control valves for regulating the flow of gases and liquids, automatic liquid-flow control machines and instruments; devices f...