We personally believe in each of these products and highly recommend them. If you're just ordering ProArgi-9+, then use the left side. If you're just ordering e9, then use the right side.
If you want to order both products, then call Dan Hammer directly at 1-800-966-3012. He can combine your order at the best possible price. Just tell him “Bill and Denise Referred Me” so Dan knows you're associated with me.
Bill and Denise Easter