Let's get packing, bike packing that is! From Revelate Designs:

The Gas Tank™ is a high end, high volume top tube bag for carrying a ton of food and other gear. It offers substantial storage in an easy access case. Zip open a side for one-handed access while riding or open up both when stopped for full panel access to the contents.

Fill it with M&M's, tools, a camera, bear spray, and whatever you need to have close at hand.

Features

• One-handed zipper access while riding
• Wrap-around water-resistant zipper to keep your gear dry
• Fully padded with closed-cell foam
• Interior lined with yellow fabric for greater visibility
• Hook and loop interior divider for organizing small stuff
• Adjustable height daisy chain front attachment with a spacer block to clear stem clamp bolts
• Top tube strap has gripper material with double back wrap for bomber stability

Sizing

• Length: 9"
• Height at stem: 5"
• Width at stem: 2.5"
• Tapers down to 1.5" tall and 1.5" wide along the top tube

Specifications

• Weight:  3.5 oz
• Volume:  70-80 cu in
• Materials:  VX42 X-pac; 1050 denier domestic ballistics nylon; 420 denier yellow lining; closed cell foam padded tube sections.