Bear Bones Bikepacking: The AlpKit tapered dry bag.
Tailfin develops dry bag storage system designed specifically around Cargo Cages | road.cc
Bassdash Waterproof TPU Backpack 24L Roll-Top Dry Bag with Rod Holder for Fishing, Hiking, Camping, Kayaking, Rafting - blue - 24L US : Amazon.co.uk: Sports & Outdoors