Among these were a relay booster for telegraph lines and a fire-safetycurtain for theaters.
其中包括电报线路的继电调压器和剧院防火帘。
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Mention that it is required to put a laser safetycurtain around the exposed laser access panels, when performing maintenance or service, if the laser system is not in it's own locked room.
The double-faced hollow toughened glass provides good sound insulation, heat insulation and safety. Installing power-operated or magnetic control shutter will save you the trouble of curtain cleaning.