The Big Daddy 2 bike rack bag by BiKASE comes with a large main compartment with a seam-sealed liner, making the internal bag waterproof and drop down panniers on each side, adding extra storage for when needed! The Big Daddy 2 bike rack bag fits on all standard size rear bicycle racks using 4 straps to keep the bag tight and secure! - RF seam sealed internal liner - waterproof zipper on main storage compartment - water bottle/drink holder that will fit multiple size bottles - bungee net on top for added storage - drop down expandable side panniers - shoulder strap included - reflective accents - designed to fit most racks - dimensions: 13" x 9" x 8" (with panniers) - 1400 cubic inches, includes panniers