To perform a user seal check on a 3M valved, cup shaped disposable respirator, place both hands completely over the respirator and inhale.The respirator should collapse slightly.是什么意思_To perform a user seal check on a 3M valved, cup shaped disposable respirator, place both hands completely over the respirator and inhale.The respirator should collapse slightly.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句