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. 20mm Crimp Top Aluminum Caps often come in various colors, which can help with sample identification, organization, or differentiation of different products or solutions. The cap material is a metal aluminum cover. 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.