Lowe Alpine's Airstream Lite Drysacs have an air-permeable base allowing air to escape as you compress the items inside - resulting in better compression than standard drybags.
Lowe Alpine says: Durable, waterproof stuffsac that lets air out and keeps contents dry. Colours vary on which size you choose (Small - orange, Medium - blue, Large - red, XLarge - purple)
The Lowe Alpine Airstream Lite Drysacs have an air-permeable eVENT base that allows the sack to be rolled to the smallest size possible consistent with the contents. A compression strap at the base can be mated to the closure buckles and used to compress the contents but its a limited arrangement because there's only two straps as opposed to the usual 4 on standard compression sacks. A good choice for Down sleeping bags and clothing. Colours vary on which size you choose.