23 Exercises Proven to Build a Muscular Chest and Enormous Arms

1:48 in this video

The setup is the same as it would be for a standard Dumbbell Bench Press except the dumbbells are rotated so they are parallel to the body rather than a 45-degree angle.

Similar to a Close-Grip Bench Press, this positioning will put more focus on the triceps.

This is often a suitable option for individuals with shoulder issues as it takes some pressure off the shoulder joint.

By increasing the angle of the bench to about 40 degrees, you're shifting some emphasis off the lower pecs and shifting it to the upper pecs and shoulders.

Once you're using a bench that's up over 65 degrees or so, you're essentially performing a version of a Seated Shoulder Press.