Kit 4D is an add-on to allow you to install an Ipex-1 booster board in your smart controller instead of a regular remote. This is not available for order on the website currently. Please request via a support ticket before placing your order. For your configuration the following items will be shipped:
The Step-down power module may have been part of your standard kit order to match your aircraft. If your regular kit code ends in DD, you won't need another step-down power module since it was included as part of your base kit.