Shock absorber assembly comprising - a first sheath slidingly housing inside it a first piston along a first sliding direction (X'-X'), the first sheath being filled with hydraulic fluid, the first piston comprising a first stem extending from the first sheath and a first head contained inside the first sheath, the first stem and the first sheath being suitable to be mechanically connected respectively to a wheel (20, 20 ', 20 ") and to a frame or vice versa, - a second sheath slidingly housing inside it a second piston along a second sliding direction (X"'-X"), the second sheath being filled with hydraulic fluid, the second piston comprising a second stem extending from the second sheath and a second head contained inside the second sheath, the second stem and the second sheath being suitable to be mechanically connected respectively to a wheel (20, 20', 20") and to a frame or vice versa, - wherein the first and second sheaths (48, 64) are fluidly connected to each other by means of at least one upper duct and a first interconnection duct passing through a control body, - the first and second piston (52, 68) moving according to a motion of compression or juxtaposition of the respective first and second heads (60, 76) to the upper duct, and a motion of extension or distancing of the respective first and second heads (60, 76) from the upper duct, - wherein said control body houses at least one damping valve comprising a damping plate having holes suitable to allow a calibrated passage of the hydraulic fluid channelled by the first and second sheaths (48, 64) towards the control body, - said control body houses a control valve connected to actuator means to be movable, in a regulation stroke, from an unlocked position, in which it does not interfere with said upper duct and a locked position, wherein said upper duct is occluded, characterised in that the first interconnection duct is located at a lower end of the first and second sheath (48,64) opposite the upper duct with respect to the heads (60,76) of the pistons (52, 68), so as to permit the passage of hydraulic fluid between the first and second sheaths (48,64) during the extension motions of the respective pistons (52,68). - a first sheath slidingly housing inside it a first piston along a first sliding direction (X'-X'), the first sheath being filled with hydraulic fluid, the first piston comprising a first stem extending from the first sheath and a first head contained inside the first sheath, the first stem and the first sheath being suitable to be mechanically connected respectively to a wheel (20, 20 ', 20 ") and to a frame or vice versa, - a second sheath slidingly housing inside it a second piston along a second sliding direction (X"'-X"), the second sheath being filled with hydraulic fluid, the second piston comprising a second stem extending from the second sheath and a second head contained inside the second sheath, the second stem and the second sheath being suitable to be mechanically connected respectively to a wheel (20, 20', 20") and to a frame or vice versa, - wherein the first and second sheaths (48, 64) are fluidly connected to each other by means of at least one upper duct and a first interconnection duct passing through a control body, - the first and second piston (52, 68) moving according to a motion of compression or juxtaposition of the respective first and second heads (60, 76) to the upper duct, and a motion of extension or distancing of the respective first and second heads (60, 76) from the upper duct, - wherein said control body houses at least one damping valve comprising a damping plate having holes suitable to allow a calibrated passage of the hydraulic fluid channelled by the first and second sheaths (48, 64) towards the control body, - said control body houses a control valve connected to actuator means to be movable, in a regulation stroke, from an unlocked position, in which it does not interfere with said upper duct and a locked position, wherein said upper duct is occluded, characterised in that the first interconnection duct is located at a lower end of the first and second sheath (48,64) opposite the upper duct with respect to the heads (60,76) of the pistons (52, 68), so as to permit the passage of hydraulic fluid between the first and second sheaths (48,64) during the extension motions of the respective pistons (52,68). - wherein the first and second sheaths (48, 64) are fluidly connected to each other by means of at least one upper duct and a first interconnection duct passing through a control body, - the first and second piston (52, 68) moving according to a motion of compression or juxtaposition of the respective first and second heads (60, 76) to the upper duct, and a motion of extension or distancing of the respective first and second heads (60, 76) from the upper duct, - wherein said control body houses at least one damping valve comprising a damping plate having holes suitable to allow a calibrated passage of the hydraulic fluid channelled by the first and second sheaths (48, 64) towards the control body, - said control body houses a control valve connected to actuator means to be movable, in a regulation stroke, from an unlocked position, in which it does not interfere with said upper duct and a locked position, wherein said upper duct is occluded,