Collars advanced technology is using the properties of some specific plastic materials. The active ingredient is incorporated inside the plastic matrix itself and is being released from this matrix under a constant speed over a long period of time. The active ingredient migrates to the surface of the plastic under the form of micro drops or powder depending on the active molecule. Since the release is very slow, the product can be effective for several months. At the end of the product life, the content of the active ingredient inside the plastic is very small and the collar will become more rigid; you will then need to replace the collar with a new one.