These 20mm Crimp Top Aluminum Caps are typically made of aluminum, which is a lightweight and corrosion-resistant metal. Aluminum provides excellent sealing properties, ensuring the integrity of the sample within the vial. The cap features a crimp top design, which means it can be securely attached to the vial by using a crimping tool. This process involves crimping the cap around the vial’s neck, creating a tight and tamper-evident seal. The design with a 9.5mm hole in the center of the cover can be used for headspace analysis. Standard GC and HPLC sample bottles can be used for autosampler and sample storage. 20mm Crimp Top Aluminum Caps often come in various colors, which can help with sample identification, organization, or differentiation of different products or solutions.