Inserts for 2 mL Standard Opening Vials - Inserts | Sigma . Sigma-Aldrich Online Catalog Product List: Inserts for 2 mL Standard Opening Vials Product # Description Add to Cart 27400-U Insert for 2 mL standard opening vial, 4.6 mm I.D. volume 0.05 mL, conical clear glass, bottom spring, O.D. × H 4 mm × 25 mm, pkg of. 2 Ml Vial at Thomas