A system comprising: - a device adapted to be run on a tubing string into a wellbore; and - an actuating body, wherein the device comprises: - a tubular body (11, 23) adapted to form a portion of the tubing string, - at least one inlet for enabling the entry of a fluid into the tubing string, wherein the at least one inlet is at least one aperture in a wall of the tubular body (11, 23); - a close mechanism for closing the at least one inlet, wherein the close mechanism comprises a movable member that is movable from a first position, whereby fluid can be received from an outside of the tubing string into the tubing string through the at least one inlet, to a second position for closing the at least one inlet; and - a catcher coupled to the movable member, wherein, in a configuration for immerging the tubing string in a fluid inside the wellbore, the movable member is in the first position and the at least one inlet is open for letting the fluid enter the tubing string, wherein the close mechanism is operable to close by means of the actuating body, wherein the movable member is movable from the first position to the second position by a force exerted by the actuating body, the actuating body being received in the catcher, wherein the catcher receives the actuating body in an internal bore of the device and wherein the actuating body is an object inserted into a top end of the tubing string, wherein the object is fluid-dissolvable, such that, when the device has been run on a tubing string into a wellbore in the configuration for immerging the tubing string, and when the object has been received in the catcher and the movable member has been moved from the first position to the second position, the object dissolves after a time in the presence of the fluid that has entered into the tubing string through the at least one inlet, characterized in that the device comprises a destructible barrier positioned downhole in relation to the at least one inlet, wherein the destructible barrier isolates the interior of the tubing string for allowing fluid in the isolated interior of the tubing string to be pressurised when the at least one inlet is closed. - a device adapted to be run on a tubing string into a wellbore; and - an actuating body, - a tubular body (11, 23) adapted to form a portion of the tubing string, - at least one inlet for enabling the entry of a fluid into the tubing string, wherein the at least one inlet is at least one aperture in a wall of the tubular body (11, 23); - a close mechanism for closing the at least one inlet, wherein the close mechanism comprises a movable member that is movable from a first position, whereby fluid can be received from an outside of the tubing string into the tubing string through the at least one inlet, to a second position for closing the at least one inlet; and - a catcher coupled to the movable member, wherein, in a configuration for immerging the tubing string in a fluid inside the wellbore, the movable member is in the first position and the at least one inlet is open for letting the fluid enter the tubing string, wherein the close mechanism is operable to close by means of the actuating body, wherein the movable member is movable from the first position to the second position by a force exerted by the actuating body, the actuating body being received in the catcher, wherein the catcher receives the actuating body in an internal bore of the device and wherein the actuating body is an object inserted into a top end of the tubing string, wherein the object is fluid-dissolvable, such that, when the device has been run on a tubing string into a wellbore in the configuration for immerging the tubing string, and when the object has been received in the catcher and the movable member has been moved from the first position to the second position, the object dissolves after a time in the presence of the fluid that has entered into the tubing string through the at least one inlet, characterized in that the device comprises a destructible barrier positioned downhole in relation to the at least one inlet, wherein the destructible barrier isolates the interior of the tubing string for allowing fluid in the isolated interior of the tubing string to be pressurised when the at least one inlet is closed.