The Arm Dip Station is a challenging and very effective movement that primarily targets your triceps, but your glutes and quads also get worked secondarily. Now, this is not a beginner’s exercise or for someone who does not have adequate upper body strength. So, performing the chair dip with two arms is recommended in this case.
But, once you build up more tricep strength, you can advance to the single-arm version. The benefits are extremely useful when you have limited equipment and you can actually use any solid platform for this exercise. So, make the dip arm a part of your tricep routine.