Osprey UltraLight 20 Dry Sack, One Size

Osprey Ultralight Drysacks are fully seam-taped with a roll top closure making them fully waterproof. The real genius is the rectangular shape, which utilizes the maximum of space within a bag.
Roll top waterproof closure
Waterproof coated fabric and seams
Rectangular shape for efficient packing
Pull tab on the bottom