Review on FUZADEL Rotating Arm Rests: Ergonomic Support for Computer Desk | Office Arm Pads with 360° Rotation and Wrist Rest by Matt Schmick

I use this at work with my desk. As long as my elbow is roughly in the middle of the pivot point, it swings fine from mouse to keyboard. Matching the movement of the armrest to the natural movement of your elbow is probably the most important part of this job. It sometimes kicks in when the articulation doesn't match the actual movement of my hand, but overall it has greatly reduced my fatigue. My jacket size is 44 if that can help you determine if this product is for you.