Heat shrink end caps are designed to protect the hose after prior cleaning. They eliminate the possibility of re-contaminating the hose, which is problematic and occurs with traditional methods (ill-fitting plastic plugs or caps inserted or screwed into the ends can leave particles generated by shearing the material with the thread). Heat shrink end caps leave no contaminants behind. As long as they are on the ends of the previously cleaned hose, we are guaranteed that it remains clean. Removing such a cap involves pulling the black strip (located along the cap) towards the end of the hose. The caps are for single use only and cannot be reused.