Primary muscles worked are the back. Secondarily are the biceps.

Connect the single handle to the lower split weight pulley. Bend slightly forward from your waist. Keep your back arched and your knees slightly bent. Your arm should be fully extended at the starting position. Keep your arm close to your body and pull until you hand is parallel with your body. Lower the weight in a controlled motion. Repeat with the other arm when you have completed your reps.