T-slot adapter kit for skybox nx, grandtour and cbx cargo boxes. add the smart-slot™ kit 6 to the skybox nx, grandtour, and cbx cargo boxes for an even sleeker profile on t-slot crossbars. this easy-to-use hardware kit replaces the standard mounting hardware, and directly attaches to a t-slot channel on your crossbars. it works with all yakima® t-slot crossbars as well as most other t-slot crossbars.