This is a brand-new (tags still on) Louis Garneau cycling bag with shoulder strap.
There is a mount that goes on the bike and the bag then attaches to the position and has a fast release for effortlessly taking it with you when you secure your bike.
Quite just like this:.
http://www.louisgarneau.com/ca-en/product/310738/1493520/Urban/CITY_HB-5.5_BAG.
Originally cost $39.99 plus tax.
Can be gotten at Main and Danforth also.