Originally Posted by
rodar y rodar
That`s how "dry sacks" come. The collar is a semi-rigid strip of plastic that helps keep a nice seal when you roll up the top. Important if you have possibility of precip, but you can save a few grams and a few bucks if you`re sure you`ll be dry or if it`s otherwise waterproofed- everything zip locked inside or the whole bag is going into something else that`s already waterproof.
Most of my bike touring and bushwalking is in our winter hence the preference for dry sacks. I need them for bushwalking particularly so tend to go with them.
Andrew