The Dip Arm is an exercise used in strength training, Narrow shoulder-width dips mainly train the triceps. Wide arm training places extra stress on the pectorals muscles, similar in respect to the way a wide grip bench press would focus more on the pectorals and less on the triceps
Here are your movements: wrist curls, wrist extensions, handshake curls (bending your thumb toward your forearm and back) using a dumbbell, and squeeze (Captains of Crush have a terrific selection of hand grippers that can sit on your desk).
For all four moves, start with a weight that stops you in your tracks at 10–12 reps for the first set, 15–20 the second, 20–25 the third, and 25-plus for the final set. You may want to have a friend drive you home after one week of this.