The Topeak Aero Wedge Large Bike Saddle Bag easily stores your riding essentials. It's expandable, easy to secure, and has a safety clip for attaching a light. FEATURES: Aerodynamic and expandable design Quick Release Buckle system fits all railed saddles 3M(TM) Reflective strip and safety light clip Interior compartment has a mesh pocket for smaller items Material: 1200 Denier polyester SPECS: Capacity: 1.48 - 1.97 liters Seat post diameter: Fits 27.2mm - 34.9mm Dimensions: 9.1" x 5.5" x 5.1" Weight: 5.81 oz.