These universal plug caps for test tubes are durable for easy application under varying temperatures and storage conditions. Each cap seals the tube inside or over the rim, making it usable in both ways. The design of the test tube plug caps helps to prevent leaking and maintains the integrity of the sample. Their material is flexible, so they will stay in place while in use. This test tube lid design is suitable for centrifuge, test, and specialty tubes and prevents damage on the tube rim. They are available in different colors, which are good for labeling to avoid confusion, and they come in 1,000-count packs.

• They are durable for easy application under varying temperatures and storage conditions
• Each cap seals the tube inside or over the rim making it usable in both ways
• Fits tubes with the following diameters: 10, 11, 12, 13, 15, 16 mm.