Ortlieb says about the Bike-Packer Classic QL2.1
A pair of rear panniers with lid closure and waterproof front compartments: Quick-Lock2.1 system for racks with up to 16mm in tubing diameter. Bags sport PU-coated Cordura fabric: an inner pocket: large reflectors: base feet: and a shoulder strap.
Accessories available separately: Packing Cubes / Commuter Insert for Panniers: Carrying System Bike Pannier: Anti-theft device (E125): Outer pocket 1.8 L: Mesh pocket: Bottle cage: QL2.1 hook 18 mm (E211) & 20 mm (E193).