100% Waterproof Construction: Welded Seams And Szip Waterproof Zipper; No Zipper Flap Required. Attaches With Or Without A Roof Rack: Attach The Carrier'S Straps To A Vehicle’S Roof Rack Or Use The Car Clips To Attach The Straps To A Vehicle'S Door Frame Weather Molding. Easy To Install: Your Bag Comes With Everything You Need To Load It Up, Attach It, And Hit The Road In Minutes! Includes Carrier, (4) Attachment Straps, (4) Car Clips, And Stuff Sack With Sewn-In Set Up Guide. X-Large Capacity Design: 18 Cubic Feet Of Storage; 48" L X 36" W X 18" H; Designed For Suvs And Minivans.