I wanted a method for carrying in the essentials for the daily commute without having to fit a pannier rack, and a handlebar bag was out of the question because of lights and gear cables, and this little beauty is just the ticket.
It's very easy to fit and can be easily taken off for the weekend club run. It is small - so don't expect to be able to take your shirts into work - but it is spot on for carrying in lunch and, ahem, smalls.
There is a tag on the bag for a rear light, but a light just can't be clipped on as it will bounce off. So either a secure fitting light is needed or you'll need to go for a light that fits to the seat stay.
In summary, if you want something for carrying the daily essentials that you can fit to the bike and forget about - this is the product for you.