— the sealed case allows you to use the camera underwater. The camera, usually, is completely hidden in such a container, shooting is carried out through a transparent front wall, and control is carried out using buttons and switches on the case itself, which duplicate the camera controls and transmit user commands to them. Note that underwater cases can have different allowable immersion depths; this detail should be clarified according to the manufacturer's documentation.
Note that even if the camera has a high degree of water protection, underwater housing may still be required for effective underwater recording. This is because action camera lenses are usually designed for recording in the air; water, on the other hand, has different optical characteristics, and if water comes into direct contact with the camera lens, normal shooting may not be possible. The underwater case corrects this situation: when using it, the camera lens contacts the air inside the underwater case, which makes it possible to effectively record the underwater world. However, there are many cameras where the lens is covered with a transparent sealed cover that allows you to shoot without a case. For such models, an additional container can be useful from another point of view: it often has a greater allowable immersion depth than an unprotected camera.
