This exercise is very similar to the bench press except performed with dumbbells instead of a barbell.
The Differences: The dumbbell press is kind of like a combination of the flye and bench press. It works the pecs slightly differently and can be performed on an incline or a decline (just like bench press) to target the major or minor pectorals. The dumbbell press also activates more balance receptors than bench pressing.
Execution: Lie with your back on the bench, with your feet flat on the floor. Hold the dumbbells as if you were holding a barbell that was in the downward position of a bench press motion. Extend your arms upward and inward as one motion (in other words, do not go up and then in, combine the two directions into one path) so that the dumbbells meet infront of your chest. Slowly lower the dumbbells back down and outward to resume the origional position.