A valve for administering drug fluid, comprising: - a rotational axis, - at least one inlet (210a-f; 220) for receiving a drug fluid, - a valve outlet, - a house body, - a rotor, and - a manipulating device configured to manipulate said rotor to be rotated about said rotational axis, wherein said house body having: - an inner cavity, - an inner circumferential sealing surface, - a top part and a bottom part which are mutually spaced along the rotational axis, wherein the bottom part is located, more distally from the manipulating device along the rotational axis than the top part, and wherein said top part has an outer circumferential surface with a circumference larger than said inner circumferential surface, and protruding ribs on said outer circumferential surface, wherein said rotor having: - a circumferential sealing surface, - an annular collar which has a circumference larger than said outer circumferential surface of said house top part, and which at least partly encloses said top part of said house body, and said annular collar having axial recess grooves arranged to engage with said protruding ribs of the house body, - an annular protruding ring, and - a passageway (310, 330) presenting an inlet arranged in the circumferential sealing surface of the rotor, and an outlet arranged co-axially with said rotational axis and always in fluid communication with said valve outlet, wherein said rotor is rotatable about said rotational axis and arranged at least partly within said inner cavity of said house body, said circumferential sealing surface of said rotor being in sealing engagement with said inner circumferential sealing surface of said house, and said rotor being configured to be rotated into any selected one of a plurality of rotational positions defined by said recess grooves engaging with said protruding ribs, and wherein the top part of the house body includes an annular recess and the annular collar extends axially past the protruding annular ring of said rotor to provide a locking mechanism enabled by a radially outward force from the top part of the house body being counter acted by a radially inward force from the enclosing collar. - a rotational axis, - at least one inlet (210a-f; 220) for receiving a drug fluid, - a valve outlet, - a house body, - a rotor, and - a manipulating device configured to manipulate said rotor to be rotated about said rotational axis, wherein said house body having: - an inner cavity, - an inner circumferential sealing surface, - a top part and a bottom part which are mutually spaced along the rotational axis, wherein the bottom part is located, more distally from the manipulating device along the rotational axis than the top part, and wherein said top part has an outer circumferential surface with a circumference larger than said inner circumferential surface, and protruding ribs on said outer circumferential surface, - an inner cavity, - an inner circumferential sealing surface, - a top part and a bottom part which are mutually spaced along the rotational axis, wherein the bottom part is located, more distally from the manipulating device along the rotational axis than the top part, and wherein said top part has an outer circumferential surface with a circumference larger than said inner circumferential surface, and protruding ribs on said outer circumferential surface, wherein said rotor having: - a circumferential sealing surface, - an annular collar which has a circumference larger than said outer circumferential surface of said house top part, and which at least partly encloses said top part of said house body, and said annular collar having axial recess grooves arranged to engage with said protruding ribs of the house body, - an annular protruding ring, and - a passageway (310, 330) presenting an inlet arranged in the circumferential sealing surface of the rotor, and an outlet arranged co-axially with said rotational axis and always in fluid communication with said valve outlet, - a circumferential sealing surface, - an annular collar which has a circumference larger than said outer circumferential surface of said house top part, and which at least partly encloses said top part of said house body, and said annular collar having axial recess grooves arranged to engage with said protruding ribs of the house body, - an annular protruding ring, and - a passageway (310, 330) presenting an inlet arranged in the circumferential sealing surface of the rotor, and an outlet arranged co-axially with said rotational axis and always in fluid communication with said valve outlet, wherein said rotor is rotatable about said rotational axis and arranged at least partly within said inner cavity of said house body, said circumferential sealing surface of said rotor being in sealing engagement with said inner circumferential sealing surface of said house, and said rotor being configured to be rotated into any selected one of a plurality of rotational positions defined by said recess grooves engaging with said protruding ribs, and wherein the top part of the house body includes an annular recess and the annular collar extends axially past the protruding annular ring of said rotor to provide a locking mechanism enabled by a radially outward force from the top part of the house body being counter acted by a radially inward force from the enclosing collar.