Make the most of the space inside your packs with the ortlieb ultralight ps10 drybag thanks to the valve on the dry bag you will be able to expel all the air out of the back allowing for more compression reducing the pack volume to a minimumas the name suggests the ps10 is also ultra lightweight and is also 100 waterproof making it a perfect addition to any non waterproof pack the roll top closure is supported with a stiffener bar and once rolled 6 times completes the waterproof closure