A:AnswerA phone case is shown because the battery is substantially thicker (and heavier) than the samsung battery. So, when you use the new battery, it won't fit with the old backing. That's why they send you a new case
A:AnswerYes, I have a Galaxy G5S and this battery will work. Now I will say that they will send you a new cover with this battery. My old battery was thinner. This battery is thicker and would never have worked with the old cover. If they had not sent the new cover with the battery it would not have worked.