Features Choose high-quality, environmentally friendly, high-density synthetic cork. Acid and alkali resistance, corrosion resistance, heat resistance, heat insulation. Good elasticity and high coefficient of friction to ensure stable flask placement. The flask holder is made of high temperature and high pressure pressing, and the thickness is 30mm. Suitable for all kinds of round bottom glassware, convenient and practical. Features: -Choose high-quality, environmentally friendly, high-density synthetic cork. -Acid and alkali resistance, corrosion resistance, heat resistance, heat insulation. -Good elasticity and high coefficient of friction to ensure stable flask placement. -The flask holder is made of high temperature and high pressure pressing, and the thickness is 30mm. -Suitable for all kinds of round bottom glassware, convenient and practical. Specification: Material: cork Outer diameter: 80mm/3.1in, 100mm/3.9in,110mm/4.3in,120mm/4.7in,140mm/5.5in,160mm/6.3in (Optional) Height:30 mm /1.2in Weight: Approx.30g~60g/1.1oz~2.1oz Service guarantee ：100% brand new product, all refund if unsatisfied If you have any questions, please contact our professional customer service team. Package List