Samsung GH81-28604A battery-cover adhesive tape is a replacement adhesive part for the Galaxy S26 Plus. It fits beneath the rear battery cover and is intended for re-gluing components after the phone has been disassembled.
Using the specified adhesive provides a purpose-made way to refit the cover during a repair. The listing notes that restoring water resistance after disassembly depends on the device, so the tape alone does not guarantee that result.