Optimally, get one with a HEPA “completely sealed” system.

最好带有HEPA（高效空气过滤器）“完全密封”系统。

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Only use completely sealed metal containers for intermediate bearing.

只能将完全密封的金属容器用于中间轴承。

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In a larger range of pressure and temperature can be completely sealed.

在较大的压力和温度范围内，能实现完全密封。

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It can fold in on itself to become a completely sealed concrete block, preventing any of the undead from getting in.

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But the well may not be completely sealed off until at least until August, when BP hopes to complete a relief well.

CNN: BP robots steer cap to spewing well

To dampen vibration (hard drives like these have platters that spin thousands of times per minute), the Blade Runner's case is heavy, solid and completely sealed.

WSJ: A Hard Drive With Quiet Style | Geek Chic