This includes the two main parts of the adjustable arm, thumbscrew, plastic washer, and rubber washer for the Atlas Short support.
This arm is the only difference between the Atlas Short and the Atlas Standard or Atlas Tall. If you have a Standard or Tall, you can purchase this arm to convert it to a Short.
NOTE: The holes where the arm attaches to the magnet are not threaded. The screw will self-tap the hole and create the threads when inserted for the first time.