ClikSeal™ 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 ClikSeal™ 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