An apparatus for providing user access to and protecting a touch sensitive device underwater, comprising: a waterproof casing comprising an inner cavity configured to receive the touch sensitive device, the casing comprising: a first area of the casing for providing user access to the touch sensitive device; a transparent first membrane arranged to cover at least part of the first area of the casing; wherein the inner cavity is configured to receive the touch sensitive device so that a user interface of the touch sensitive device is adjacent to the first membrane of the first area; a non-conductive fluid arranged in the inner cavity to provide a gap between the user interface of the touch sensitive device and the first membrane; and the casing further comprising: a pressure control membrane arranged to cover at least part of a second area of the casing; and a pressure control element operationally connected to the pressure control membrane; characterized by: the fluid being incompressible fluid; the pressure control element being configured to flexibly bend the pressure control membrane to pressurize the fluid and change pressure of the pressurized non-conductive incompressible fluid; and the pressure control element being user operable via a rotatable user controller (15, 17, 19). a waterproof casing comprising an inner cavity configured to receive the touch sensitive device, the casing comprising: a first area of the casing for providing user access to the touch sensitive device; a transparent first membrane arranged to cover at least part of the first area of the casing; wherein the inner cavity is configured to receive the touch sensitive device so that a user interface of the touch sensitive device is adjacent to the first membrane of the first area; a first area of the casing for providing user access to the touch sensitive device; a transparent first membrane arranged to cover at least part of the first area of the casing; wherein the inner cavity is configured to receive the touch sensitive device so that a user interface of the touch sensitive device is adjacent to the first membrane of the first area; a non-conductive fluid arranged in the inner cavity to provide a gap between the user interface of the touch sensitive device and the first membrane; and the casing further comprising: a pressure control membrane arranged to cover at least part of a second area of the casing; and a pressure control element operationally connected to the pressure control membrane; a pressure control membrane arranged to cover at least part of a second area of the casing; and a pressure control element operationally connected to the pressure control membrane; characterized by: the fluid being incompressible fluid; the pressure control element being configured to flexibly bend the pressure control membrane to pressurize the fluid and change pressure of the pressurized non-conductive incompressible fluid; and the pressure control element being user operable via a rotatable user controller (15, 17, 19). the fluid being incompressible fluid; the pressure control element being configured to flexibly bend the pressure control membrane to pressurize the fluid and change pressure of the pressurized non-conductive incompressible fluid; and the pressure control element being user operable via a rotatable user controller (15, 17, 19).