Waterproof. Good deal!
The "small" fits a Mystery Ranch 3 Day Assault Pack; the "large" fits a Mystery Ranch Overload + Daypack lid.
The material feels like cotton fabric, not Gore-texy. But I ran it under a faucet for a good while, and my hand underneath was indeed dry.
It doesn't naturally fold up very compact, but compresses nicely with other items.
You can't tell it's not Multicam unless you have an on-the-spectrum level of attention to detail.