This is a whitewater dry bag for storeing items in your canoe and keeping them dry, its 860mm long by 300mm wide.

also a plastic BDH bottle, l used it store my first aid kit in, at 200mm x 100mm it was a ideal size for that, the lid does not have a waterproof seal you need to put tape over the joint or a rubber seal.

selling off a few other kayak bric a brac if you would like to check them out.