Go over to REI where you can grab this REI Flash 18 Pack for ONLY $19.99 (reg.$34.50) plus FREE Shipping!
This pack offers a removable back panel pad that doubles as a sit pad and a hydration-compatible design that includes a hose exit port and an internal sleeve for a reservoir (sold separately). And, it converts into a stuff sack when you turn it inside out!
Thanks, Collin!