只有身体和精神的双重力量才能打开、关闭那道门。
And you have to shut the door. So it's literally physical strength to open and shut the door.
金属旋塞表面压向阀座环软支座表面，如阀芯和阀座环表面是同心的，就能得到双重严密的关闭。
Metal cock ring soft seat surface pressure to the bearing surfaces, such as the valve core and valve seat is concentric ring surface can be a double tight closure.
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