Caulk strip is made with PVC and High quality butyl rubber guarantees.Smooth and enjoyable surface will never turn black,be mildew or break.With the anti-bacterium added,the environment-friendly material that is mildew-free,without poison,free from smell can protect people health.Can be used for a long period of 5 years,with a low cost per y ear.Self-adhesive,user-friendly and no tool needed.