Yakima Jetstream Crossbar Lightweight aluminum extrusion Engineered with jettruss structure for reliable strength. Comes with 2 Crossbars and 4 Endcaps Jetflow aerodynamic shape designed in a wind tunnel to ultimately reduce noise and drag T-slot with smartfill push-down infill to attach mounts while maintaining air flow over the bar T-slot compatible with whispbar bike, boat and ski mounts. It's exceptionally aerodynamic, incredibly strong, lightweight, and really quiet on the move Clear anodized alloy finish seamlessly enhances Look of the vehicle Available in three sizes and two colors Works with Yakima BaseLine, RidgeLine, TimberLine and Skyline towers only.