Package & Size--You will get 30pcs black resin bottle caps. The size is about about 23mm/0.9 inch in diameter, 12mm/0.47 inch thick; inner diameter is about 18mm/0.71 inch. Please make sure that the diameter of the bottle mouth is 18mm before purchase, otherwise it will not be applied.Premium Material--The set of bottle caps is made of resin material, which is strong and durable and can withstand some degree of bottle pressure. It can also be reused multiple times and can meet the needs of long-term use.Good Sealing Effects--If the resin cap is inserted into the sealing area, it can form a tight closure to prevent liquid leakage, providing you with a good sealing effect.Easy to Use--The black cover has a raised ridge around the entire circumference for easy gripping and sealing, and the liner forms an ultra-tight seal by providing tight sealing protection.Wide Application--The resin bottle cap is widely used for a variety of daily chemicals, cosmetics, household products and other soft and hard packaging bottles and hose caps, is a very practical daily use accessories.