This is an upgrade kit that you can use to upgrade your 1-way remote starter previously purchased here into a 2-way kit.
This kit includes a new antenna, a new 2-way remote, and a new 1-way remote. Note that your existing 1-way remotes will not work with the new antenna.
Once you have the kit on-hand, you will need to swap the antenna over, then pair the remotes. This process takes about 5 minutes and a video will be sent to you when the product is shipped on how to do this.