Tube Style pads are sewn closed at the bottom. For installation they slide onto the crossbar from an open end. For Aerodynamic style crossbars on standard racks. Typical 2.75″x.75″ (Thule Aero Bar) (Yakima Core Bar) (Yakima Jet Stream). Vinyl is a durable, low cost option with a large color selection. Vinyl is subject to fading. Aero size will fit most oval factory installed racks. Sold in pairs, packaged in poly bag with header. Made in USA.