ZOS Halo Testing Holder
Included with each ZOS Halo is a testing holder. This holder performs two functions. First, by inserting the ZOS Halo Stopper into the tester, it will perform a test to tell you if the cartridge is still good, or if it needs to be replaced by displaying a green (good) or red (change) light. The holder is also a sealed container that will preserve the life of the cartridge between uses.
Because the cartridge is such a powerful oxygen absorber, exposure to oxygen will significantly reduce cartridge life. When not in use, the ZOS Halo should always be store in this protective holder.