Even if it is made of an impervious material, it is important to properly seal the roll top opening of the dry bag. If not properly sealed, it may open during outdoor activities and water may enter the interior. How to seal dry bags?
First, put the items you need in it. Make sure to leave at least 1/4 of the bag at the top as spare space.
Remove the remaining air inside. If you want the dry bag to float on the water while it is floating, you can also leave the air inside.
Adjust the vinyl top of the dry bag. Fold up like dog ears.
Fold the fabric three times down or up to the black folding band.
The buckles are then merged together to secure a suitable seal.