I mainly like this day pack for how it flattens out and can be placed in any type of luggage or backpack without taking up space.  However, this day pack is not of the quality I thought it would be.  I noticed some loose threads hanging, but it didn't appear as though it would unravel ( I hope not).  It's also for basically lightweight stuff you need while out, like a jacket, water bottle and few site seeing brochures/maps etc and items you might pick up along the way.  But, as I mentioned before, it definitely will save space when packed.