It is a Alpinestars Tech Aero tank bag
Used once. Been in the closet since.
Has both magnet and straps. Rain cover, map pocket, holes for ear bud wires or hose for water bag. Several pockets. Expandable. Detaches from base plate and has back straps with quick disconnect. Literally everything in a bag you could ask for
I bought an Axio tank bag to go with my Axio tail bag
These are $190 new. Looking for $150 shipped
http://www.alpinestars.com/moto/bags-and-packs/tech-aero-tank-bag-black-o-s.html#.UftD3Y0qYiY
~~SOLD~~