Yakima tracks - what size T-nut?

Yakima Smart-Slot Kit 1 yakima t slot adapter Add the SmarT-Slot™ Kit 5 to the Yakima TopWater™ box for an even sleeker profile on T-Slot Crossbars This easy hardware kit replaces the standard mounting yakima t slot adapter : T Slot Bolts for Thule, Yakima Roof Rack Cross Bars, Platform, Cargo Basket, Stainless Square T Track Bolt Adapter to Secure

yakima smartslot kit 1 Mounts TopWater Fishing Rod Box on T-slot Crossbars Includes installation tool and hardware Fits most T-slot crossbars Yakima 8004094 SmarT-Slot Kit 5