These lids are made from plastic materials, strong and durable, not easy to crack, with a long using life. The seal screw cap has a raised ridge on the surface, which make it anti-slip, easy to screw tightly or loosely. With good sealing, it can effectively prevent leakage, to ensure the quality. Features -Color:Black -Material:Plastic -Size:4.00X4.00X1.50cm/1.57X1.57X0.59in -Tight Closure: These bottle caps are designed with cone area, insert its cone part into your bottles for a tight closure -Leakproof: Designed to prevent leakage and give you an airtight seal, provide the sealing performance you want -Good Choice: Good workmanship, and these screw caps will be a good choice for you - : With fine workmanship, the cap is durable and not easy to break, and provide a long serving time -Ample Supply: There are enough quantity of screw caps that can meet your different kinds of needs Package list: 16