A hollow, compressible or rigid hollow body has mechanical retaining devices such as sound generators, scent capsules, LED lights and vibrating mechanisms and identifying or responding detection elements held, secured and locked therein without the use of any solvents, glues, sonic welding, spin welding or other bonding materials. The hollow contaminant-free bodies are particularly useful for animals and recreation. Some of the above contain carcinogens harmful to animals if ingested.