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What is a vial adapter?
A plastic spike that seats onto a stopper once and leaves a screw-on port, so you can draw without a needle and without making a new hole each time. Full explanation →
Why it matters when you shop
A plastic spike with a luer-lock hub on top: push it through a vial stopper once and every syringe afterwards connects without a needle. It has to match the stopper size (13 mm is the common vial, 20 mm the large one), and it stays on the vial, so one adapter per vial.
What to look for on the listing
- The stopper size it fits, 13 mm or 20 mm, stated in the listing.
- Individually wrapped and sterile.
- A luer-lock syringe to go with it; the adapter has no needle and does not need one.
Go deeper
- Guide: Mixing (reconstituting) a vial, step by step
- Comparison: Luer Lock Vs Luer Slip
- Tool: Product Finder for this category
- All terms: the glossary
Products where this number appears
Reviewed 2026-09-03. Definitions describe equipment, not treatment. Affiliate links open your own country's Amazon store; your price is the same.