For any smartphone I've owned I have always used a protective case, either an Otterbox or similar TPU case. That is, until recently. My current phone is a rugged model with its own built in case, Blackview BV9600 Pro. The corners are rubberized with gripped ridges. Just think of a turtle with its own shell. My phone is supposedly waterproof and dustproof too although I haven't tested that out fully. Even if I wanted to put a case on it I have had trouble finding one for my model. At 12 mm thick the phone on its own is already pretty hefty.