I own two bicycle specific backpacks. The Ortlieb Velocity shown above and a Camelback Trans Alp. Both are excellent bags, but they lack one detail that mystifies me - a loop to attach a red blinkie. I can't imagine why anyone would build anything that is meant to be used facing the rear on a bike that does not include the simple, inexpensive, but exceedingly useful feature of a small loop to clip a flashing light to. Sure I prefer a light attached to a bike, but that isn't always possible and heck what I really prefer is multiple flashing lights so one on my bike, one on my bag and one on my helmet would be awesome.