Device comprising: a body defining a containment volume for a fluid for medical use, said body comprising a terminal, said terminal defining a conduit configured to put said containment volume into communication with the outside; a cap support integral with said body and disposed outside said containment volume, said cap support defining an internal volume housing said terminal; a tip cap associable with said cap support by first constraint means and associable with said terminal by second constraint means, said tip cap being configured to assume at least: - a first stable position in which the tip cap is integral with said cap support, in said first stable position a first portion of the tip cap being housed in the internal volume of said cap support and a second portion of said tip cap emerging from the internal volume of said cap support; and - a second stable position in which the tip cap is integral with said terminal and completely housed in said internal volume of said cap support; wherein the containment volume is in communication with the outside when said tip cap assumes said first stable position and is sealed when said tip cap assumes said second stable position, wherein the tip cap and the cap support have both an axisymmetric structure, in particular a cylindrical structure, said first constraint means comprising at least one circumferential groove formed on the external lateral surface of the tip cap and one or more reliefs emerging from the inner lateral surface of the cap support towards the internal volume of said cap support, said one or more reliefs being configured to engage, in particular to fit into, said at least one circumferential groove when the tip cap is in the first stable position and wherein at least one of the external lateral surface of the tip cap and the inner lateral surface of the cap support has one or more recesses defining, when the tip cap is in the first stable position, one or more gaps between the tip cap and the cap support. a body defining a containment volume for a fluid for medical use, said body comprising a terminal, said terminal defining a conduit configured to put said containment volume into communication with the outside; a cap support integral with said body and disposed outside said containment volume, said cap support defining an internal volume housing said terminal; a tip cap associable with said cap support by first constraint means and associable with said terminal by second constraint means, said tip cap being configured to assume at least: - a first stable position in which the tip cap is integral with said cap support, in said first stable position a first portion of the tip cap being housed in the internal volume of said cap support and a second portion of said tip cap emerging from the internal volume of said cap support; and - a second stable position in which the tip cap is integral with said terminal and completely housed in said internal volume of said cap support; - a first stable position in which the tip cap is integral with said cap support, in said first stable position a first portion of the tip cap being housed in the internal volume of said cap support and a second portion of said tip cap emerging from the internal volume of said cap support; and - a second stable position in which the tip cap is integral with said terminal and completely housed in said internal volume of said cap support; wherein the containment volume is in communication with the outside when said tip cap assumes said first stable position and is sealed when said tip cap assumes said second stable position, wherein the tip cap and the cap support have both an axisymmetric structure, in particular a cylindrical structure, said first constraint means comprising at least one circumferential groove formed on the external lateral surface of the tip cap and one or more reliefs emerging from the inner lateral surface of the cap support towards the internal volume of said cap support, said one or more reliefs being configured to engage, in particular to fit into, said at least one circumferential groove when the tip cap is in the first stable position and wherein at least one of the external lateral surface of the tip cap and the inner lateral surface of the cap support has one or more recesses defining, when the tip cap is in the first stable position, one or more gaps between the tip cap and the cap support.