Keep Your Gear Bone Dry – Rain or Shine with the Duck’s Back Raincover! Don’t let the weather ruin your adventure. The Duck’s Back Raincover is a lightweight, durable, and packable solution to keep your rucksack and all your kit dry – no matter the forecast. Designed to slip on in seconds and stay put, it’s like giving your backpack its own waterproof jacket. Windproof. Waterproof. Worry-proof.