@bethyousey thanks for the question! Can we confirm which model of the Advanced Elements kayak you are considering: the AdvancedFrame or the Attack Pro? It appears that the backbone would be an optional accessory, if you want even higher performance from the AdvancedFrame model. Although this is not an item we carry online at REI, it is an item we may be able to special order for you directly from Advanced Elements, once our stores reopen fully. Hope this helps!