Description General description Engineered for a "push on" fit in NMR tubes and ampules. The unique design provides a penetration point for cannulation and a dual seal inside the tube and on the outer sleeve. Will not break delicate, thin-wall tubing. Manufactured from one certified raw material formulation for absolute consistency in all sizes, from lot to lot. Storage Note for Natural Rubber Septa: Store septa in a closed bag out of sunlight to retard blooming, which is the formation of a whitish film on the surface of the rubber. Blooming is a natural process and does not affect performance. Remove visible bloom by washing or wiping off before use. Legal Information Precision Seal is a registered trademark of Sigma-Aldrich Co. LLC