Quarks also carry fractional electric charges, but, since they are confined within hadrons whose charges are all integral, fractional charges have never been isolated. Note that quarks have electric charges of either ⁠+ + 2 / 3 ⁠ e or ⁠− + 1 / 3 ⁠ e, whereas antiquarks have corresponding electric charges of either ⁠− + 2 / 3 ⁠ e or ⁠+ + 1 / 3 ⁠ e.