Top left: AIA 193 Å image at 12:39:31 UT that features the jet threads (T1 and T2) and flare as indicated by the white arrows. The red/blue lines stand for the contours of positive and negative polarities of the HMI LOS magnetogram at 12:39:32 UT. Top right: running-difference image of STEREO-B/EUVI in 195 Å at 12:46:27 UT, showing the top segment of the jet. The dashed line stands for the projection of the plane-of-the-sky on the EUV image. The angle included between the jet and plane-of-the-sky is labeled with θ. Bottom panels: top view (left) and side view (right) of the 3D magnetic field lines. The red/blue lines represent closed/open magnetic field lines.