A printing fluid cartridge configured to be inserted into a cartridge mounting portion in an insertion direction intersecting a gravitational direction in an upright position, the printing fluid cartridge comprising: a front face oriented toward the insertion direction when the printing fluid cartridge is inserted into the cartridge mounting portion; a rear face positioned opposite the front face with respect to the insertion direction and oriented toward the removal direction, when the printing fluid cartridge is inserted into the cartridge mounting portion; a top face extending between the front face and the rear face, and facing upward when the printing fluid cartridge is in the upright position; a chamber configured to store printing fluid therein; an electrical interface (75, 76, 77) disposed at the top face, such that the electrical interface (75, 76, 77) is exposed to an exterior of the printing fluid cartridge; a printing fluid supply portion comprising a printing fluid supply opening and configured to supply the printing fluid from an interior of the chamber to an exterior of the chamber via the printing fluid supply opening, wherein the printing fluid supply portion is positioned at the front face; wherein the electrical interface (75, 76, 77) is positioned above the printing fluid supply portion when the printing fluid cartridge is in the upright position, and positioned more rearward than the printing fluid supply opening with respect to the insertion direction; wherein the printing fluid cartridge in the upright position has a width in a width direction, a height in a height direction, and a depth in a depth direction, wherein the width direction, the height direction, and the depth direction are perpendicular to each other, and the depth direction is parallel with the insertion direction, wherein the printing fluid cartridge further comprises a recess which is opened upward in the height direction when the printing fluid cartridge is in the upright position, wherein the recess is positioned more forward than the electrical interface (75, 76, 77) with respect to the insertion direction, and the recess and the electrical interface (75, 76, 77) intersects a plane which is parallel with the height direction and the depth direction, wherein the electrical interface (75, 76, 77) is positioned above the recess when the printing fluid cartridge is in the upright position; wherein the recess is opened on one side or both sides of the printing fluid cartridge in the width direction. a front face oriented toward the insertion direction when the printing fluid cartridge is inserted into the cartridge mounting portion; a rear face positioned opposite the front face with respect to the insertion direction and oriented toward the removal direction, when the printing fluid cartridge is inserted into the cartridge mounting portion; a top face extending between the front face and the rear face, and facing upward when the printing fluid cartridge is in the upright position; a chamber configured to store printing fluid therein; an electrical interface (75, 76, 77) disposed at the top face, such that the electrical interface (75, 76, 77) is exposed to an exterior of the printing fluid cartridge; a printing fluid supply portion comprising a printing fluid supply opening and configured to supply the printing fluid from an interior of the chamber to an exterior of the chamber via the printing fluid supply opening, wherein the printing fluid supply portion is positioned at the front face; wherein the electrical interface (75, 76, 77) is positioned above the printing fluid supply portion when the printing fluid cartridge is in the upright position, and positioned more rearward than the printing fluid supply opening with respect to the insertion direction; wherein the printing fluid cartridge in the upright position has a width in a width direction, a height in a height direction, and a depth in a depth direction, wherein the width direction, the height direction, and the depth direction are perpendicular to each other, and the depth direction is parallel with the insertion direction, wherein the printing fluid cartridge further comprises a recess which is opened upward in the height direction when the printing fluid cartridge is in the upright position, wherein the recess is positioned more forward than the electrical interface (75, 76, 77) with respect to the insertion direction, and the recess and the electrical interface (75, 76, 77) intersects a plane which is parallel with the height direction and the depth direction, wherein the electrical interface (75, 76, 77) is positioned above the recess when the printing fluid cartridge is in the upright position; wherein the recess is opened on one side or both sides of the printing fluid cartridge in the width direction.