Blackburn MTN Bar Bag mounts on top of your bike's handlebar and stem.  Three velcro fasteners will hold the bag firmly to your bar/stem while riding, but remove easily if needed.  No tools required.  This durable black bag has a 150 cubic inch capacity main pouch good to hold your wallet, cell phone, repair supplies and food for a day of riding.  There is a zippered clear weather-tight pouch on top of the bag where you slip in a map for easy viewing.  The pack converts to a fanny pack with the included waist strap.