The black jacket cover are a simple, easy and effective way to bring darkness to a test tube set-up. Ants like dark spaces, making them feel secure. 
 
You can always gently slide the jacket back to be able to view your colony. Gently as to not produce any vibrations or sudden shakes to avoid stressing your ants.  The red film does not protect from light as these black jackets do, but they allow us to observe the colony without moving or touching anything; they are very space-effective and simple to use. 
 
Made with black dark plastic with a matte finish to ensure as much light is absorbed as possible. 
 
The inside diameter of the jacket is slightly bigger than the outside diameter of most standard common test tubes; please carefully select your size. 
 
The jacket measures 40 mm tall; combined with our "test-tube inserts," "feeding inserts," and "cotton water keepers," they make for a very sophisticated set-up.