Purpose: To build mass and muscle density of the upper pecs. By rotating the dumbbell through the motion, you are engaging the upper/middle pecs.
Execution: Lie back on the incline bench with your feet planted on the floor. Holding the weights at a slightly neutral grip, press the weight up rotate your hands as to point your thumbs to each other. Rotate as far as possible before reaching the upper portion of the rep. Squeeze the pecs and lower the weight slowly to your start position before completing another rep.