We have been doing this trap movement for years. Its really the best shrug exercise I have ever done when done correctly. I'm sure you could use db's, plate or some other variation but since we have the kettle bells and we don't use them for anything else except maybe a door prop they work great for this.
Be sure to really squeeze at the top while the kettle bells bounces. Keep the band and bounce under control and you will reap the benefits and possible create a little hump on your neck!