I bought this to seal the back cover of my wife's htc u11 phone after a battery change. The application needle made applying the sealant much easier. The battery died so I had to take it apart again and put a new battery in. The seal is flexible but holds up well. I will continue to use it for my electronics when changing batteries, screens etc. Works very well but be careful because it dries fairly quickly so be ready to replace the part once you have finished applying the glue. It was easy to clean with a cotton swab dipped in alcohol and heat with a heat gun.