ClikSealâ„¢ containers are leak-resistant and ideal for pneumatic tube systems. The audible "click" you hear when you tighten the lid assures you that the cap is seals and ready for transport. All ClikSealâ„¢ containers have a blue screw-on cap designed to enable stacking of multiple containers. Item has a sterility-seal and patient I.D. label affixed to the container with lines for date, number, name, and doctor. For Pneumatic Tube Systems- Specimen Container, 4 oz, Label & Gray Lid, Polybag, 100/cs (60 cs/plt) Stock Item