| 摘要 |
The frame member, designed to form part of a door or window frame, for example, can be made from aluminium, PVC, a synthetic resin or plastics material, and is made from assembled sections with and without ventilation ports. The assembled sections are preferably designed to make up a square-section tube with ventilation ports in opposite vertical sides, with one side made from two components with apertures, able to slide relative to one another to vary the degree of ventilation and controlled by a stop plate at one end.
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