Start: Attach a stirrup handle to a low pulley. Grab the handle with your nondominant hand and stand sideways to the weight stack so your dominant side is closest to it. Bend your working elbow not quite 90 degrees, with the inside of that forearm facing the side of your torso.
Finish: Pull the handle out and up so your hand is just above your head. You should look like you're about to throw a pitch. Pause, then return to the starting position. Finish your set with that arm, then repeat with your other arm.