Think Tank Photo Glass Taxi Backpack Fits 500mm f/4 unattached, 300mm f/2.8 with standard DSLR attached, 70200mm f/2.8 with hood in the shooting position attached to standard DSLR Can be used as a shoulder bag or a backpack Specially designed zippers hold their position to avoid accidental opening of the main compartment Foam collar for large glass Exterior Dimensions: 8.5 W x 17 H x 9.5 D (21.6 x 43.2 x 24.1 cm), Internal Dimensions: 8.3 W x 16.3 H x 8 D (21.1 x 41.4 x 20.3 cm), Weight: 23.7 lbs (0.91.7 kg) Depending on accessories used