Material - The cover is made of good aluminum and plastic, smooth and burr-free after opening,  offering a secure seal for glass vials. Good Seal - The equipped plastic-aluminum lid ensures the tightest seal and reduces the possibility of sample evaporation. This crimp top vial provides a good seal for long-term sample storage. How to Use - To open, flip off the plastic cap and remove the aluminum seal using pliers if necessary. The flip off seal can withstand high temperatures. But this cover is fully tear-off, and when you tear off its plastic cover, the aluminum cover becomes unusable. Application - Our  Flip Off Caps can be used in the laboratory and at home, with a good sealing effect and convenient storage. Suitable for oral liquid bottles, original solution bottles, essential oil bottles, freeze-dried bottles, etc. Caps Material: Aluminum, Plastic Suitable for: 13 mm/0.5 inch Glass Vial Inside diameter: 13 mm/0.5 inch Outer diameter: 15 mm/0.6 inches Height: 7 mm/0.3 inches Package Content: 100 x Flip Off Caps