product description: Features: rubber stopper, good elasticity, excellent grade. Uses: It is used to block round holes, fish tank openings, sewer openings, wall openings, glass openings, with good sealing, simple and practical. Product size: see the picture below(If your aperture is 20mm, you can choose the size of 23*17*26 for the plug, take the middle number of the largest diameter and the smallest diameter, and so on.)
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