| 摘要 |
The utility of a cover for vents or drains is improved by having a unitary, integral fastening means which can be used to either secure the covering so securely that mutilation of the cover may be required to remove the cover or that the cover may be easily removed and replaced. The cover can be formed from any polymer with any desired surface configuration, i.e., hole size and shape, and can be used to modify existing covers or as the original cover for a hole or vent. The fastening means when integral is made of the same material as the cover and can be easily expanded and secured by pressure elements. Since the normal sleeve has been replaced by the integral fastener which is part of the cover, no relative rotation of the sleeve and pressure means can occur.
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