20mm Aluminim Cap - Color: Silver

20 mm Aluminum Cap Specifications

1. Diameter & Fit

• Nominal diameter: ~20 mm (fits containers with a 20 mm neck) this is the key size reference. For screwtop closures this corresponds to standards like 20-410 or 20-400 threads (20 mm outer neck diameter with specific thread pitch).

2. Cap Type / Closure Style

• Crimp caps: Designed for sealing lab vials (headspace, GC, autosampler). They are crimped around the vial neck and often used with septa.

• Screw caps: Standard threaded caps for bottles/jars (20-410/20-400).

• Tin/aluminum caps: More generic closures (may be combined with liners).
  Products above include both crimp vial caps and general aluminum closures.

3. Material

• Main body: Lightweight aluminum (often anodized or untreated). Aluminum provides corrosion resistance and is recyclable.

• Sealing liner (if present): Foam (EPE), plastisol, PTFE, silicone, or butyl liners depending on application.

4. Septa / Liner for Crimp Caps

• Septa size: ~20 mm 3 mm thick (diameter thickness).

• Center hole: Commonly ~9.5 mm for autosampler needle access in GC applications.

5. Thread Standards (Screw Caps)

• 20-410: Standard continuous thread for many bottles/containers (20 mm diameter, 410 thread spec).

• 20-400: Another common thread spec (20 mm diameter, 400 thread pitch); height ~9.6 mm typical.

6. Dimensions

• Outer diameter: ~20 mm nominal (actual cap OD often slightly larger); inner diameter ~20.2 mm for aluminum-plastic caps.

• Height: Varies by cap style typical small screw caps ~8 13 mm; crimp caps vary based on skirt and septa.

7. Uses

• Crimp caps: Laboratory headspace vials, GC/GC-MS sample sealing.

• Screw caps: Cosmetics, pharmaceuticals, food & beverage, essential oil bottles, small chemical containers.