Tamrac photo backpacks are made from water-proofed materials and have giant rain flaps, so in general, they don't require a raincover. When extra security is desired, these M.A.S.™ Raincovers provide it with a double waterproof-coated PowerGrid™ nylon that protects everything except the back of the backpack and the harness. Folded in their pouch, they attach to any of the M.A.S.™ backpack attachment points.