It are designed to securely seal vials with an internal neck diameter of approximately 47.0 - 48.0mm. These high-quality, sterile stoppers ensure a reliable, airtight seal, protecting vial contents from contamination. Perfect for use in laboratory settings, these stoppers are ideal for storing and transporting chemicals, biological samples, and other materials. The pack of 75 provides a cost-effective solution for laboratories with high-volume sealing needs, ensuring consistent and dependable sealing performance for various laboratory applications.