Standard size: Outer diameter:6.1cm/ 2.4inch. inside diameter:4.2cm/1.65inch. thickness:1 cm/0.4inch. fit for 5 - 6 mm thickness tempered glass and tabletop，only fits inside a 2 inch hole in a glass, you can refer to size chart before placing an order; If your table top material is thicker or your hole is bigger or smaller it will not fit Material: the umbrella hole ring plug and cap set is made of clear silicone, soft and durable, not easy yellowing; Color：Black Function: these umbrella hole rings can help to stabilize patio umbrellas, reducing and preventing scratches or dents on unstable umbrella poles.Useful cap accessories, the cap included can decorate the look of the tabletop when your umbrella is not in use. Wide application: the table umbrella hole ring is great for coffee shop, bar, milk tea shop, yard or other glass outdoors patio table. Package Content :1 Set Hole Ring and Cap Set.