Catalog number: CHCC20-2. Use Aijiren Tech™ SureSTART™ 20 mm Crimp Caps with crimp vials that have a 20 mm opening, including our SureSTART 20 mL Glass Crimp Top Headspace Vials (Level 1). Select Level 1 caps for chromatography approved, cost optimized products that are suitable for everyday analyses and compatible with all instrument