Many athletes try to do dryland exercises that are very specific to swimming technique. This makes obvious sense because you want to build strength and muscle memory for swimming and not other athletic movements. However, to get a better impact and a better understanding of how the dryland activity translates to your swimming stroke, you can use equipment.
Check out the video below that shows how some pieces of equipment will help you understand what your body is doing on the Ergometer, and how you can translate that power in the pool. Note that even though the demonstrator puts on the Forearm Fulcrum incorrectly, the point he is trying to make is certainly not lost:
Just doing swim-specific dryland exercises isn’t always enough. Using equipment such as a snorkel or Forearm Fulcrum while you swim will allow you to focus on the movements and strength that you have built out of the water.