Hi @JDugan - Thanks for bringing this question to the community!
The spray skirts that are compatible with the Advanced Elements tandem inflatable kayaks are the Packlite Spray Skirt and the Touring Spray Skirt - both made by Advanced Elements. While we do not currently carry these, one way that we can help you with this purchase will be through our special order process, where we place an order for you directly with the vendor. Because this is an in-store only process, you will need to contact your local REI to ask about availability.
Let us know if you have any additional questions and we'll be happy to help!