Used primarily as a heat stabilizer in polyvinyl chloride (PVC) plastics, especially in rigid and transparent PVC products. It prevents degradation during processing and extends the lifespan of the material by resisting discoloration and maintaining structural integrity under heat exposure. Also exhibits biocidal properties, making it useful in antifouling coatings for marine applications to prevent the growth of algae, barnacles, and other organisms on ship hulls and underwater structures. Its use has declined in some regions due to environmental concerns related to organotin toxicity.